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https://weather.gov

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
82
GRADE
B
FIX
2
REVIEW
5
PASS
6
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
97
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
67
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
88
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
73
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

760 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.23 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

760 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.44 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
15
6 PASS 5 REVIEW 2 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (1.2 MiB of 1.2 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

B
Page Weight Budget
1.2 MB transferred, 49 requests
REVIEW
1.2 MB transferred, 49 requests
Info::
Page weighs 2.5 MB (1.2 MB transferred)
Warning::
JavaScript is 595 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 595 KB
Info::
49 HTTP requests
Info::
Estimated 0.26 g CO2 per page load
1.2 MB / 2.4 MB budget
1.2 MB transferred
49 requests
0.26 g CO2 per page load
Images 614.1 KiB 48%
JavaScript 595.0 KiB 47%
HTML 30.1 KiB 2%
CSS 24.7 KiB 2%
Other 12.1 KiB 1%
Other 597 B 0%
0 2.4 MB 4.9 MB
Under budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

C
Image Optimization
Action
19 images, 0 KB saveable
REVIEW
19 images, 0 KB saveable
Warning::
https://www.weather.gov/wwamap/png/US.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.weather.gov/bundles/templating/images/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.weather.gov/bundles/templating/images/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
19 images 614 KB
0 oversized -0 KB
19 legacy format
3 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

C
JS Bundles
Action
17 scripts, 288 KB unused
REVIEW
17 scripts, 288 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-736J...: 106 KB unused (72%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-736J...: 63 KB unused (43%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.weather.gov/js/jquery-ui-1.10.3.custom...: 60 KB unused (90%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-CSLL...: 59 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 288 KB
288 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0V&cx=c&gtm=4e64h1149 KB106 KB (72%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0V149 KB63 KB (43%)✓3rd
https://www.weather.gov/js/jquery-ui-1.10.3.custom.min.js67 KB60 KB (90%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L148 KB59 KB (40%)✓3rd
https://www.weather.gov/js/jquery-cookie.js2 KB—✓3rd
https://www.weather.gov/js/topNavMenu.js1 KB—✓3rd
https://www.weather.gov/js/NidsESRI.js2 KB—✓3rd
https://www.weather.gov/js/nwsexit.js2 KB—✓3rd
https://www.weather.gov/js/jquery-1.10.2.min.js35 KB—✓3rd
https://www.weather.gov/js/MyForecastWidget.js4 KB—✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

C
Page Weight Inventory
Action
49 resources · 1.2 MB · 288 KB savings available
REVIEW
49 resources · 1.2 MB · 288 KB savings available
Warning::
Page weight 252 KB over 1MB target
Got: 1.2 MB Expected: ≤ 1 MB
Info::
~288 KB of savings available
Warning::
48 third-party resources (100% of weight)
Info::
1 resources over 200KB
49 resources · 1.2 MiB · 48 third-party 252.5 KiB over 1MB target
Image 48% · 614.1 KiB
JavaScript 47% · 595.0 KiB
Document 2% · 30.1 KiB
CSS 2% · 24.7 KiB
Other 1% · 12.6 KiB

~287.9 KiB of savings available

Remove unused JavaScript: 287.9 KiB
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
JS Execution Cost
299ms total JS execution
PASS
299ms total JS execution
Info::
https://www.googletagmanager.com/gtag/js?id=G-CSLL...: 91ms CPU time
Info::
https://www.weather.gov/: 82ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-736J...: 69ms CPU time
Info::
Unattributable: 57ms CPU time
Warning::
Third-party scripts: 299ms (100% of total)

Main Thread Breakdown

Script Evaluation 48% Other 24% Script Parsing & Compilation 13% Style & Layout 9%
ScriptTotalScriptingParse/CompileParty
https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L91ms72ms18ms3rd
https://www.weather.gov/82ms1ms1ms3rd
https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0V69ms57ms12ms3rd
Unattributable57ms2ms0ms3rd
A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
Network Waterfall
49 requests over 672ms
INFO
0 ms 500 ms 1.0 s FCP 760 ms LCP 1.2 shttps://weather.gov// https://weather.gov/ — 301 — 111 B — 47 ms — h2https://www.weather.gov/www.weather.gov/ https://www.weather.gov/ — 200 — 30.1 KiB — 93 ms — h2https://www.weather.gov/css/weatherstyle.csswww.weather.gov/css/weatherstyle.cs... https://www.weather.gov/css/weatherstyle.css — 200 — 5.2 KiB — 44 ms — h2https://www.weather.gov/css/template.csswww.weather.gov/css/template.css https://www.weather.gov/css/template.css — 200 — 3.5 KiB — 22 ms — h2https://www.weather.gov/css/myfcst.csswww.weather.gov/css/myfcst.css https://www.weather.gov/css/myfcst.css — 200 — 2.0 KiB — 23 ms — h2https://www.weather.gov/css/ForecastSearch.csswww.weather.gov/css/ForecastSearch.... https://www.weather.gov/css/ForecastSearch.css — 200 — 987 B — 45 ms — h2https://www.weather.gov/css/pointforecast.csswww.weather.gov/css/pointforecast.c... https://www.weather.gov/css/pointforecast.css — 200 — 3.5 KiB — 23 ms — h2https://www.weather.gov/css/jqueryui10_3_1custom/jquery-ui-1.10.3.custom.min.csswww.weather.gov/css/jqueryui10_3_1c... https://www.weather.gov/css/jqueryui10_3_1custom/jquery-ui-1.10.3.custom.min.css — 200 — 6.2 KiB — 46 ms — h2https://www.weather.gov/js/jquery-1.10.2.min.jswww.weather.gov/js/jquery-1.10.2.mi... https://www.weather.gov/js/jquery-1.10.2.min.js — 200 — 35.4 KiB — 32 ms — h2https://www.weather.gov/js/jquery-ui-1.10.3.custom.min.jswww.weather.gov/js/jquery-ui-1.10.3... https://www.weather.gov/js/jquery-ui-1.10.3.custom.min.js — 200 — 67.1 KiB — 58 ms — h2https://www.weather.gov/js/jquery.hoverIntent.minified.jswww.weather.gov/js/jquery.hoverInte... https://www.weather.gov/js/jquery.hoverIntent.minified.js — 200 — 1.3 KiB — 27 ms — h2https://www.weather.gov/js/ForecastSearch.jswww.weather.gov/js/ForecastSearch.j... https://www.weather.gov/js/ForecastSearch.js — 200 — 6.8 KiB — 29 ms — h2https://dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=DOC&sub-agency=NOAA&yt=true&pga4=G-736JJ6NL0Vdap.digitalgov.gov/Universal-Federa... https://dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=DOC&sub-agency=NOAA&yt=true&pga4=G-736JJ6NL0V — 200 — 9.4 KiB — 16 ms — h3https://www.weather.gov/js/topNavMenu.jswww.weather.gov/js/topNavMenu.js https://www.weather.gov/js/topNavMenu.js — 200 — 1.4 KiB — 29 ms — h2https://www.weather.gov/js/NidsESRI.jswww.weather.gov/js/NidsESRI.js https://www.weather.gov/js/NidsESRI.js — 200 — 1.9 KiB — 30 ms — h2https://www.weather.gov/js/nwsexit.jswww.weather.gov/js/nwsexit.js https://www.weather.gov/js/nwsexit.js — 200 — 1.9 KiB — 56 ms — h2https://www.weather.gov/bundles/templating/images/header/header.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/header/header.png — 200 — 9.1 KiB — 50 ms — h2https://www.weather.gov/css/search.csswww.weather.gov/css/search.css https://www.weather.gov/css/search.css — 200 — 966 B — 30 ms — h2https://www.weather.gov/bundles/templating/images/header/header_doc.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/header/header_doc.png — 200 — 2.0 KiB — 39 ms — h2https://www.weather.gov/bundles/templating/images/top_news/important.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/top_news/important.png — 200 — 2.2 KiB — 32 ms — h2https://www.weather.gov/js/jquery-cookie.jswww.weather.gov/js/jquery-cookie.js https://www.weather.gov/js/jquery-cookie.js — 200 — 1.6 KiB — 29 ms — h2https://www.weather.gov/js/MyForecastWidget.jswww.weather.gov/js/MyForecastWidget... https://www.weather.gov/js/MyForecastWidget.js — 200 — 4.5 KiB — 59 ms — h2https://www.weather.gov/bundles/templating/css/wwamap/wwamap.csswww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/css/wwamap/wwamap.css — 200 — 2.3 KiB — 41 ms — h2https://www.weather.gov/wwamap/png/US.pngwww.weather.gov/wwamap/png/US.png https://www.weather.gov/wwamap/png/US.png — 200 — 359.9 KiB — 69 ms — h2https://www.weather.gov/wwamap/png/ak.pngwww.weather.gov/wwamap/png/ak.png https://www.weather.gov/wwamap/png/ak.png — 200 — 36.7 KiB — 38 ms — h2https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0Vwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0V — 200 — 148.5 KiB — 169 ms — h2https://www.weather.gov/source/nws/govshutdown.jswww.weather.gov/source/nws/govshutd... https://www.weather.gov/source/nws/govshutdown.js — 404 — 664 B — 150 ms — h2https://www.weather.gov/wwamap/png/hi.pngwww.weather.gov/wwamap/png/hi.png https://www.weather.gov/wwamap/png/hi.png — 200 — 17.5 KiB — 41 ms — h2https://dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.jsdap.digitalgov.gov/web-vitals/dist/... https://dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js — 200 — 4.5 KiB — 8 ms — h3https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4Lwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L — 200 — 147.5 KiB — 143 ms — h2
0 ms 500 ms 1.0 s FCP 760 ms LCP 1.2 shttps://weather.gov// https://weather.gov/ — 301 — 111 B — 47 ms — h2https://www.weather.gov/www.weather.gov/ https://www.weather.gov/ — 200 — 30.1 KiB — 93 ms — h2https://www.weather.gov/css/weatherstyle.csswww.weather.gov/css/weatherstyle.cs... https://www.weather.gov/css/weatherstyle.css — 200 — 5.2 KiB — 44 ms — h2https://www.weather.gov/css/template.csswww.weather.gov/css/template.css https://www.weather.gov/css/template.css — 200 — 3.5 KiB — 22 ms — h2https://www.weather.gov/css/myfcst.csswww.weather.gov/css/myfcst.css https://www.weather.gov/css/myfcst.css — 200 — 2.0 KiB — 23 ms — h2https://www.weather.gov/css/ForecastSearch.csswww.weather.gov/css/ForecastSearch.... https://www.weather.gov/css/ForecastSearch.css — 200 — 987 B — 45 ms — h2https://www.weather.gov/css/pointforecast.csswww.weather.gov/css/pointforecast.c... https://www.weather.gov/css/pointforecast.css — 200 — 3.5 KiB — 23 ms — h2https://www.weather.gov/css/jqueryui10_3_1custom/jquery-ui-1.10.3.custom.min.csswww.weather.gov/css/jqueryui10_3_1c... https://www.weather.gov/css/jqueryui10_3_1custom/jquery-ui-1.10.3.custom.min.css — 200 — 6.2 KiB — 46 ms — h2https://www.weather.gov/js/jquery-1.10.2.min.jswww.weather.gov/js/jquery-1.10.2.mi... https://www.weather.gov/js/jquery-1.10.2.min.js — 200 — 35.4 KiB — 32 ms — h2https://www.weather.gov/js/jquery-ui-1.10.3.custom.min.jswww.weather.gov/js/jquery-ui-1.10.3... https://www.weather.gov/js/jquery-ui-1.10.3.custom.min.js — 200 — 67.1 KiB — 58 ms — h2https://www.weather.gov/js/jquery.hoverIntent.minified.jswww.weather.gov/js/jquery.hoverInte... https://www.weather.gov/js/jquery.hoverIntent.minified.js — 200 — 1.3 KiB — 27 ms — h2https://www.weather.gov/js/ForecastSearch.jswww.weather.gov/js/ForecastSearch.j... https://www.weather.gov/js/ForecastSearch.js — 200 — 6.8 KiB — 29 ms — h2https://dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=DOC&sub-agency=NOAA&yt=true&pga4=G-736JJ6NL0Vdap.digitalgov.gov/Universal-Federa... https://dap.digitalgov.gov/Universal-Federated-Analytics-Min.js?agency=DOC&sub-agency=NOAA&yt=true&pga4=G-736JJ6NL0V — 200 — 9.4 KiB — 16 ms — h3https://www.weather.gov/js/topNavMenu.jswww.weather.gov/js/topNavMenu.js https://www.weather.gov/js/topNavMenu.js — 200 — 1.4 KiB — 29 ms — h2https://www.weather.gov/js/NidsESRI.jswww.weather.gov/js/NidsESRI.js https://www.weather.gov/js/NidsESRI.js — 200 — 1.9 KiB — 30 ms — h2https://www.weather.gov/js/nwsexit.jswww.weather.gov/js/nwsexit.js https://www.weather.gov/js/nwsexit.js — 200 — 1.9 KiB — 56 ms — h2https://www.weather.gov/bundles/templating/images/header/header.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/header/header.png — 200 — 9.1 KiB — 50 ms — h2https://www.weather.gov/css/search.csswww.weather.gov/css/search.css https://www.weather.gov/css/search.css — 200 — 966 B — 30 ms — h2https://www.weather.gov/bundles/templating/images/header/header_doc.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/header/header_doc.png — 200 — 2.0 KiB — 39 ms — h2https://www.weather.gov/bundles/templating/images/top_news/important.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/top_news/important.png — 200 — 2.2 KiB — 32 ms — h2https://www.weather.gov/js/jquery-cookie.jswww.weather.gov/js/jquery-cookie.js https://www.weather.gov/js/jquery-cookie.js — 200 — 1.6 KiB — 29 ms — h2https://www.weather.gov/js/MyForecastWidget.jswww.weather.gov/js/MyForecastWidget... https://www.weather.gov/js/MyForecastWidget.js — 200 — 4.5 KiB — 59 ms — h2https://www.weather.gov/bundles/templating/css/wwamap/wwamap.csswww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/css/wwamap/wwamap.css — 200 — 2.3 KiB — 41 ms — h2https://www.weather.gov/wwamap/png/US.pngwww.weather.gov/wwamap/png/US.png https://www.weather.gov/wwamap/png/US.png — 200 — 359.9 KiB — 69 ms — h2https://www.weather.gov/wwamap/png/ak.pngwww.weather.gov/wwamap/png/ak.png https://www.weather.gov/wwamap/png/ak.png — 200 — 36.7 KiB — 38 ms — h2https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0Vwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0V — 200 — 148.5 KiB — 169 ms — h2https://www.weather.gov/source/nws/govshutdown.jswww.weather.gov/source/nws/govshutd... https://www.weather.gov/source/nws/govshutdown.js — 404 — 664 B — 150 ms — h2https://www.weather.gov/wwamap/png/hi.pngwww.weather.gov/wwamap/png/hi.png https://www.weather.gov/wwamap/png/hi.png — 200 — 17.5 KiB — 41 ms — h2https://dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.jsdap.digitalgov.gov/web-vitals/dist/... https://dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js — 200 — 4.5 KiB — 8 ms — h3https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4Lwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L — 200 — 147.5 KiB — 143 ms — h2https://www.youtube.com/iframe_apiwww.youtube.com/iframe_api https://www.youtube.com/iframe_api — 200 — 3.6 KiB — 134 ms — h2https://www.weather.gov/css/images/bg.pngwww.weather.gov/css/images/bg.png https://www.weather.gov/css/images/bg.png — 200 — 1.4 KiB — 32 ms — h2https://www.weather.gov/css/images/head_shadow.pngwww.weather.gov/css/images/head_sha... https://www.weather.gov/css/images/head_shadow.png — 200 — 996 B — 47 ms — h2https://www.weather.gov/images/nws/features/safetybannerComp.pngwww.weather.gov/images/nws/features... https://www.weather.gov/images/nws/features/safetybannerComp.png — 200 — 142.8 KiB — 27 ms — h2https://www.weather.gov/bundles/templating/images/social/x.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/social/x.png — 200 — 1.0 KiB — 25 ms — h2https://www.weather.gov/bundles/templating/images/social/facebook.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/social/facebook.png — 200 — 1.9 KiB — 29 ms — h2https://www.weather.gov/bundles/templating/images/social/youtube.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/social/youtube.png — 200 — 1.8 KiB — 21 ms — h2https://www.weather.gov/bundles/templating/images/social/rss.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/social/rss.png — 200 — 2.1 KiB — 16 ms — h2https://www.weather.gov/bundles/templating/images/footer/usa_gov.pngwww.weather.gov/bundles/templating/... https://www.weather.gov/bundles/templating/images/footer/usa_gov.png — 200 — 5.2 KiB — 16 ms — h2https://www.weather.gov/css/images/bg_footer.pngwww.weather.gov/css/images/bg_foote... https://www.weather.gov/css/images/bg_footer.png — 200 — 1.7 KiB — 14 ms — h2https://www.youtube.com/s/player/218d9d92/www-widgetapi.vflset/www-widgetapi.jswww.youtube.com/s/player/218d9d92/w... https://www.youtube.com/s/player/218d9d92/www-widgetapi.vflset/www-widgetapi.js — 200 — 10.6 KiB — 30 ms — h2https://www.weather.gov/css/images/myfcst-bg.pngwww.weather.gov/css/images/myfcst-b... https://www.weather.gov/css/images/myfcst-bg.png — 200 — 10.1 KiB — 32 ms — h2https://www.weather.gov/css/images/myfcst-block-bg.pngwww.weather.gov/css/images/myfcst-b... https://www.weather.gov/css/images/myfcst-block-bg.png — 200 — 4.8 KiB — 28 ms — h2https://www.weather.gov/images/nws/bluesky.pngwww.weather.gov/images/nws/bluesky.... https://www.weather.gov/images/nws/bluesky.png — 200 — 5.6 KiB — 86 ms — h2https://www.weather.gov/images/nws/ig.pngwww.weather.gov/images/nws/ig.png https://www.weather.gov/images/nws/ig.png — 200 — 7.1 KiB — 30 ms — h2https://region1.google-analytics.com/g/collect?v=2&tid=G-CSLL4ZEK4L&gtm=45je64h1v9131934939za200zd9131934939&_p=1776801159923&gcd=13l3lPl2l1l1&npa=1&dma_cps=a&dma=1&are=1&cid=1774420109.1776801160&frm=0&pscdl=noapi&rcb=7&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938468~117266400~118463801&dl=https%3A%2F%2Fweather.gov%2F&dt=National%20Weather%20Service&dr=&sid=1776801160&sct=1&seg=0&_tu=wA&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&ep.agency=DOC&ep.subagency=WEATHER.GOV&ep.site_topic=unspecified%3Aweather.gov&ep.site_platform=unspecified%3Aweather.gov&ep.script_source=https%3A%2F%2Fdap.digitalgov.gov%2Funiversal-federated-analytics-min.js&ep.version=20250702%20v8.7%20-%20ga4&ep.protocol=https%3A&ep.using_parallel_tracker=pga4&ep.hostname_dimension=weather.gov&tfd=536region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-CSLL4ZEK4L&gtm=45je64h1v9131934939za200zd9131934939&_p=1776801159923&gcd=13l3lPl2l1l1&npa=1&dma_cps=a&dma=1&are=1&cid=1774420109.1776801160&frm=0&pscdl=noapi&rcb=7&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938468~117266400~118463801&dl=https%3A%2F%2Fweather.gov%2F&dt=National%20Weather%20Service&dr=&sid=1776801160&sct=1&seg=0&_tu=wA&en=page_view&_fv=1&_nsi=1&_ss=1&_ee=1&ep.agency=DOC&ep.subagency=WEATHER.GOV&ep.site_topic=unspecified%3Aweather.gov&ep.site_platform=unspecified%3Aweather.gov&ep.script_source=https%3A%2F%2Fdap.digitalgov.gov%2Funiversal-federated-analytics-min.js&ep.version=20250702%20v8.7%20-%20ga4&ep.protocol=https%3A&ep.using_parallel_tracker=pga4&ep.hostname_dimension=weather.gov&tfd=536 — 204 — 549 B — 88 ms — h2https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0V&cx=c&gtm=4e64h1www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-736JJ6NL0V&cx=c&gtm=4e64h1 — 200 — 148.5 KiB — 36 ms — h2https://region1.google-analytics.com/g/collect?v=2&tid=G-736JJ6NL0V&gtm=45je64h1v9127132766za200zb9131934939zd9131934939&_p=1776801159923&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&_eu=EA&are=1&cid=1774420109.1776801160&frm=0&ir=1&pscdl=noapi&rcb=19&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938469~117266401~118463801&dl=https%3A%2F%2Fweather.gov%2F&dt=National%20Weather%20Service&dr=&sid=1776801160&sct=1&seg=0&_tu=wA&en=page_view&_fv=1&_ss=1&_ee=1&tfd=616region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-736JJ6NL0V&gtm=45je64h1v9127132766za200zb9131934939zd9131934939&_p=1776801159923&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&_eu=EA&are=1&cid=1774420109.1776801160&frm=0&ir=1&pscdl=noapi&rcb=19&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938469~117266401~118463801&dl=https%3A%2F%2Fweather.gov%2F&dt=National%20Weather%20Service&dr=&sid=1776801160&sct=1&seg=0&_tu=wA&en=page_view&_fv=1&_ss=1&_ee=1&tfd=616 — 204 — 48 B — 29 ms — h2https://www.weather.gov/favicon.icowww.weather.gov/favicon.ico https://www.weather.gov/favicon.ico — 200 — 11.9 KiB — 14 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 299ms · 326KB · €3/mo
Google Tag Manager
Tag Manager
Optional
Execution 91ms
Transfer 148 KB
Unused 40%
Monthly Cost €1/mo
www.weather.gov
Other
Optional
Execution 82ms
Transfer 30 KB
Monthly Cost €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 69ms
Transfer 149 KB
Unused 43%
Monthly Cost €1/mo
Unattributable
Other
Optional
Execution 57ms
Transfer 0 KB
Monthly Cost €1/mo

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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