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Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
81
GRADE
B
FIX
3
REVIEW
3
PASS
7
INFO
2

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

Mobile Desktop
65
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
94
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
85
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.

1.46 s

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

2.06 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.

0.400

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

1.59 s

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

2.06 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
7 PASS 3 REVIEW 3 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 (1.4 MiB of 1.4 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
Page Weight Inventory
Action
28 resources · 1.4 MB · 207 KB savings available
FIX
28 resources · 1.4 MB · 207 KB savings available
Warning::
Page weight 405 KB over 1MB target
Got: 1.4 MB Expected: ≤ 1 MB
Info::
~207 KB of savings available
Warning::
27 third-party resources (100% of weight)
Info::
1 resources over 200KB
28 resources · 1.4 MiB · 27 third-party 405.5 KiB over 1MB target
Image 38% · 542.6 KiB
JavaScript 33% · 472.0 KiB
Font 23% · 332.8 KiB
CSS 5% · 69.6 KiB
Document 1% · 11.4 KiB
Other 0% · 1.1 KiB

~207.4 KiB of savings available

Remove unused JavaScript: 207.4 KiB
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
1.4 MB transferred, 28 requests
REVIEW
1.4 MB transferred, 28 requests
Info::
Page weighs 2.6 MB (1.4 MB transferred)
Info::
Fonts are 333 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 333 KB
Info::
28 HTTP requests
Info::
Estimated 0.29 g CO2 per page load
1.4 MB / 2.4 MB budget
1.4 MB transferred
28 requests
0.29 g CO2 per page load
Images 536.9 KiB 38%
JavaScript 472.0 KiB 33%
Fonts 332.8 KiB 23%
CSS 69.6 KiB 5%
HTML 11.2 KiB 1%
Other 5.9 KiB 0%
Other 552 B 0%
Other 547 B 0%
0 2.4 MB 4.9 MB
Under budget

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

C
JS Bundles
Action
6 scripts, 207 KB unused
REVIEW
6 scripts, 207 KB unused
Warning::
https://www.ucar.edu/sites/default/files/js/js_RAg...: 78 KB unused (55%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-T9VY...: 66 KB unused (42%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=UA-332...: 63 KB unused (51%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 207 KB
207 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.ucar.edu/sites/default/files/js/js_RAg-zpb8QPCcjKQb5F2HL7w7AWFAYucNfeo_REY9bR8.js?scope=footer&delta=0&language=en&theme=ucar&include=eJxLLY1Pzs_PzkwFUrkFOZmJecmp-qlYBHXS8_PTc1LjE_MScypLMpOL9dEFdLLzi0r1s4p1IXohXBChm5RYnAoAreIpcg143 KB78 KB (55%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-T9VYFW1DZL&cx=c&gtm=4e64k0h2157 KB66 KB (42%)✓3rd
https://www.googletagmanager.com/gtag/js?id=UA-332815-87125 KB63 KB (51%)✓3rd
https://www.clarity.ms/tag/ptyiisykfv1 KB—✓3rd
https://scripts.clarity.ms/0.8.60-beta/clarity.js25 KB—✓3rd
https://www.google-analytics.com/analytics.js21 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

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
Image Optimization
6 images, 0 KB saveable
PASS
6 images, 0 KB saveable
Warning::
https://www.ucar.edu/profiles/custom/ncar_ucar_umb... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.ucar.edu/profiles/custom/ncar_ucar_umb... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
6 images 537 KB
0 oversized -0 KB
0 legacy format
2 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

A+
JS Execution Cost
324ms total JS execution
PASS
324ms total JS execution
Info::
https://www.ucar.edu/sites/default/files/js/js_RAg...: 179ms CPU time
Info::
https://www.ucar.edu/: 93ms CPU time
Info::
https://scripts.clarity.ms/0.8.60-beta/clarity.js: 51ms CPU time
Warning::
Third-party scripts: 324ms (100% of total)

Main Thread Breakdown

Script Evaluation 54% Other 16% Style & Layout 15% Script Parsing & Compilation 7% Rendering 6%
ScriptTotalScriptingParse/CompileParty
https://www.ucar.edu/sites/default/files/js/js_RAg-zpb8QPCcjKQb5F2HL7w7AWFAYucNfeo_REY9bR8.js?scope=footer&delta=0&language=en&theme=ucar&include=eJxLLY1Pzs_PzkwFUrkFOZmJecmp-qlYBHXS8_PTc1LjE_MScypLMpOL9dEFdLLzi0r1s4p1IXohXBChm5RYnAoAreIpcg179ms118ms13ms3rd
https://www.ucar.edu/93ms2ms0ms3rd
https://scripts.clarity.ms/0.8.60-beta/clarity.js51ms46ms1ms3rd
A+
Font Loading
7 fonts (333 KB)
PASS
7 fonts (333 KB)
Info::
7 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

7

333 KB total

Render-blocking

0

of 7

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.5 s LCP 2.1 shttps://fonts.gstatic.com/s/poppins/v24/pxiEyp8kv8JHgFVrJJfecnFHGPc.woff2pxiEyp8kv8JHgFVrJJfecnF... https://fonts.gstatic.com/s/poppins/v24/pxiEyp8kv8JHgFVrJJfecnFHGPc.woff2 — 7.7 KiB — 32 ms — font-display: swaphttps://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLEj6Z1xlFd2JQEk.woff2pxiByp8kv8JHgFVrLEj6Z1x... https://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLEj6Z1xlFd2JQEk.woff2 — 7.8 KiB — 34 ms — font-display: swaphttps://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/icomoon/fonts/icomoon.ttf?i45ppq=icomoon.ttf https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/icomoon/fonts/icomoon.ttf?i45ppq= — 13.3 KiB — 13 ms — font-display: swaphttps://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLCz7Z1xlFd2JQEk.woff2pxiByp8kv8JHgFVrLCz7Z1x... https://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLCz7Z1xlFd2JQEk.woff2 — 7.7 KiB — 36 ms — font-display: swaphttps://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-solid-900.woff2fa-solid-900.woff2 https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-solid-900.woff2 — 154.8 KiB — 19 ms — font-display: swaphttps://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-regular-400.woff2fa-regular-400.woff2 https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-regular-400.woff2 — 25.3 KiB — 15 ms — font-display: swaphttps://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-brands-400.woff2fa-brands-400.woff2 https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-brands-400.woff2 — 116.2 KiB — 10 ms — font-display: swap
pxiEyp8kv8JHgFVrJJfecnF... woff2 swap
Size 8 KB
Load time 32 ms
Start 588 ms
Risk FOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLEj6Z1x... woff2 swap
Size 8 KB
Load time 34 ms
Start 589 ms
Risk FOUT — text flashes from fallback to web font
icomoon.ttf ttf swap
Size 13 KB
Load time 13 ms
Start 589 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
pxiByp8kv8JHgFVrLCz7Z1x... woff2 swap
Size 8 KB
Load time 36 ms
Start 589 ms
Risk FOUT — text flashes from fallback to web font
fa-solid-900.woff2 woff2 swap
Size 155 KB
Load time 19 ms
Start 589 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
fa-regular-400.woff2 woff2 swap
Size 25 KB
Load time 15 ms
Start 595 ms
Risk FOUT — text flashes from fallback to web font
fa-brands-400.woff2 woff2 swap
Size 116 KB
Load time 10 ms
Start 595 ms
Risk FOUT — text flashes from fallback to web font
  • Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)

Fixing the unchecked items could save ~139 KB and ~278 ms

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
28 requests over 2093ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 1.5 s LCP 2.1 shttps://ucar.edu// https://ucar.edu/ — 301 — 154 B — 427 ms — h2https://www.ucar.edu/www.ucar.edu/ https://www.ucar.edu/ — 200 — 11.2 KiB — 12 ms — h2https://www.googletagmanager.com/gtag/js?id=UA-332815-87www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=UA-332815-87 — 200 — 125.3 KiB — 135 ms — h2https://www.ucar.edu/sites/default/files/css/css_-d8jtdlHKkjsQUp3LbIPJ9wse9mhG81sFAK9HYeNxYs.css?delta=0&language=en&theme=ucar&include=eJxtjEEOgzAMBD-UkidFhiwQkcSRHbdqX1-ghx7gMiuNvTuxwFeWQjl94GBhYt4S9igtJ6oT_J0METNZ7m5jMX_gMZLCNRJahNqqPoo1ysPfDFabjTnpiui0k3TIlnroKwr8Wb_YAlVaoNdL5bj_v7Wj_Lo2kfgDzsooyJnCLFx7aPuAv3HumfBSf3IoHC3jC_c9ayUwww.ucar.edu/sites/default/files/cs... https://www.ucar.edu/sites/default/files/css/css_-d8jtdlHKkjsQUp3LbIPJ9wse9mhG81sFAK9HYeNxYs.css?delta=0&language=en&theme=ucar&include=eJxtjEEOgzAMBD-UkidFhiwQkcSRHbdqX1-ghx7gMiuNvTuxwFeWQjl94GBhYt4S9igtJ6oT_J0METNZ7m5jMX_gMZLCNRJahNqqPoo1ysPfDFabjTnpiui0k3TIlnroKwr8Wb_YAlVaoNdL5bj_v7Wj_Lo2kfgDzsooyJnCLFx7aPuAv3HumfBSf3IoHC3jC_c9ayU — 200 — 2.9 KiB — 7 ms — h2https://www.ucar.edu/sites/default/files/css/css_MthkyvfFc7iesyc8jPuxJaaSkanYoI0UeRAVP3DieDA.css?delta=1&language=en&theme=ucar&include=eJxtjEEOgzAMBD-UkidFhiwQkcSRHbdqX1-ghx7gMiuNvTuxwFeWQjl94GBhYt4S9igtJ6oT_J0METNZ7m5jMX_gMZLCNRJahNqqPoo1ysPfDFabjTnpiui0k3TIlnroKwr8Wb_YAlVaoNdL5bj_v7Wj_Lo2kfgDzsooyJnCLFx7aPuAv3HumfBSf3IoHC3jC_c9ayUwww.ucar.edu/sites/default/files/cs... https://www.ucar.edu/sites/default/files/css/css_MthkyvfFc7iesyc8jPuxJaaSkanYoI0UeRAVP3DieDA.css?delta=1&language=en&theme=ucar&include=eJxtjEEOgzAMBD-UkidFhiwQkcSRHbdqX1-ghx7gMiuNvTuxwFeWQjl94GBhYt4S9igtJ6oT_J0METNZ7m5jMX_gMZLCNRJahNqqPoo1ysPfDFabjTnpiui0k3TIlnroKwr8Wb_YAlVaoNdL5bj_v7Wj_Lo2kfgDzsooyJnCLFx7aPuAv3HumfBSf3IoHC3jC_c9ayU — 200 — 65.7 KiB — 13 ms — h2https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/logo-ucar.pngwww.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/logo-ucar.png — 200 — 51.4 KiB — 5 ms — h2https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/NSF_Official_logo.pngwww.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/NSF_Official_logo.png — 200 — 209.6 KiB — 11 ms — h2https://www.ucar.edu/sites/default/files/js/js_RAg-zpb8QPCcjKQb5F2HL7w7AWFAYucNfeo_REY9bR8.js?scope=footer&delta=0&language=en&theme=ucar&include=eJxLLY1Pzs_PzkwFUrkFOZmJecmp-qlYBHXS8_PTc1LjE_MScypLMpOL9dEFdLLzi0r1s4p1IXohXBChm5RYnAoAreIpcgwww.ucar.edu/sites/default/files/js... https://www.ucar.edu/sites/default/files/js/js_RAg-zpb8QPCcjKQb5F2HL7w7AWFAYucNfeo_REY9bR8.js?scope=footer&delta=0&language=en&theme=ucar&include=eJxLLY1Pzs_PzkwFUrkFOZmJecmp-qlYBHXS8_PTc1LjE_MScypLMpOL9dEFdLLzi0r1s4p1IXohXBChm5RYnAoAreIpcg — 200 — 142.9 KiB — 14 ms — h2https://www.clarity.ms/tag/ptyiisykfvwww.clarity.ms/tag/ptyiisykfv https://www.clarity.ms/tag/ptyiisykfv — 200 — 848 B — 110 ms — http/1.1https://fonts.googleapis.com/css?family=Poppins:400,600,700fonts.googleapis.com/css?family=Pop... https://fonts.googleapis.com/css?family=Poppins:400,600,700 — 200 — 991 B — 71 ms — h2https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/UCAR-Waves-Lines-Only.pngwww.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/UCAR-Waves-Lines-Only.png — 200 — 30.8 KiB — 4 ms — h2https://www.ucar.edu/sites/default/files/2025-12/December%202025%20UCAR%20Spotlight%20Thumbnail.jpegwww.ucar.edu/sites/default/files/20... https://www.ucar.edu/sites/default/files/2025-12/December%202025%20UCAR%20Spotlight%20Thumbnail.jpeg — 200 — 194.5 KiB — 11 ms — h2https://www.ucar.edu/sites/default/files/big-picture-box/2025-08/Sun%20Earth%20Connections%20%281%29%20%281%29.jpgwww.ucar.edu/sites/default/files/bi... https://www.ucar.edu/sites/default/files/big-picture-box/2025-08/Sun%20Earth%20Connections%20%281%29%20%281%29.jpg — 200 — 26.8 KiB — 10 ms — h2https://fonts.gstatic.com/s/poppins/v24/pxiEyp8kv8JHgFVrJJfecnFHGPc.woff2fonts.gstatic.com/s/poppins/v24/pxi... https://fonts.gstatic.com/s/poppins/v24/pxiEyp8kv8JHgFVrJJfecnFHGPc.woff2 — 200 — 7.7 KiB — 32 ms — h3https://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLEj6Z1xlFd2JQEk.woff2fonts.gstatic.com/s/poppins/v24/pxi... https://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLEj6Z1xlFd2JQEk.woff2 — 200 — 7.8 KiB — 34 ms — h3https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/icomoon/fonts/icomoon.ttf?i45ppq=www.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/icomoon/fonts/icomoon.ttf?i45ppq= — 200 — 13.3 KiB — 13 ms — h2https://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLCz7Z1xlFd2JQEk.woff2fonts.gstatic.com/s/poppins/v24/pxi... https://fonts.gstatic.com/s/poppins/v24/pxiByp8kv8JHgFVrLCz7Z1xlFd2JQEk.woff2 — 200 — 7.7 KiB — 36 ms — h3https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-solid-900.woff2www.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-solid-900.woff2 — 200 — 154.8 KiB — 19 ms — h2https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-regular-400.woff2www.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-regular-400.woff2 — 200 — 25.3 KiB — 15 ms — h2https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-brands-400.woff2www.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/lib/fontawesome/webfonts/fa-brands-400.woff2 — 200 — 116.2 KiB — 10 ms — h2https://www.ucar.edu/sites/default/files/styles/xlarge_banner/public/front/2020-04/iss062e104685-BayOfBengal-hero.jpg?itok=mix1zdi4www.ucar.edu/sites/default/files/st... https://www.ucar.edu/sites/default/files/styles/xlarge_banner/public/front/2020-04/iss062e104685-BayOfBengal-hero.jpg?itok=mix1zdi4 — 200 — 23.8 KiB — 5 ms — h2https://scripts.clarity.ms/0.8.60-beta/clarity.jsscripts.clarity.ms/0.8.60-beta/clar... https://scripts.clarity.ms/0.8.60-beta/clarity.js — 200 — 25.0 KiB — 122 ms — h2https://www.googletagmanager.com/gtag/js?id=G-T9VYFW1DZL&cx=c&gtm=4e64k0h2www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-T9VYFW1DZL&cx=c&gtm=4e64k0h2 — 200 — 157.0 KiB — 57 ms — h2https://www.google-analytics.com/analytics.jswww.google-analytics.com/analytics.... https://www.google-analytics.com/analytics.js — 200 — 20.9 KiB — 61 ms — h2https://region1.google-analytics.com/g/collect?v=2&tid=G-T9VYFW1DZL&gtm=45je64k0h2v9103302364za20g&_p=1776815124228&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&gdid=dMDhkMT&_eu=AAAI&are=1&cid=1988059798.1776815125&frm=0&pscdl=noapi&rcb=10&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=0~115616985~115938465~115938469~117266401~117512543&sid=1776815124&sct=1&seg=0&dl=https%3A%2F%2Fwww.ucar.edu%2F&dt=University%20Corporation%20for%20Atmospheric%20Research%20%7C%20University%20Corporation%20for%20Atmospheric%20Research&en=page_view&_fv=1&_nsi=1&_ss=1&tfd=846region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-T9VYFW1DZL&gtm=45je64k0h2v9103302364za20g&_p=1776815124228&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&gdid=dMDhkMT&_eu=AAAI&are=1&cid=1988059798.1776815125&frm=0&pscdl=noapi&rcb=10&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=0~115616985~115938465~115938469~117266401~117512543&sid=1776815124&sct=1&seg=0&dl=https%3A%2F%2Fwww.ucar.edu%2F&dt=University%20Corporation%20for%20Atmospheric%20Research%20%7C%20University%20Corporation%20for%20Atmospheric%20Research&en=page_view&_fv=1&_nsi=1&_ss=1&tfd=846 — 204 — 547 B — 65 ms — h2https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/app-favicons/ucar/favicon.icowww.ucar.edu/profiles/custom/ncar_u... https://www.ucar.edu/profiles/custom/ncar_ucar_umbrella/themes/custom/koru/libraries/koru-base/img/app-favicons/ucar/favicon.ico — 200 — 5.7 KiB — 7 ms — h2https://k.clarity.ms/collectk.clarity.ms/collect https://k.clarity.ms/collect — 204 — 276 B — 427 ms — http/1.1https://k.clarity.ms/collectk.clarity.ms/collect https://k.clarity.ms/collect — 204 — 276 B — 101 ms — http/1.1
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 324ms · 179KB · $4/mo
www.ucar.edu
Other
Optional
Execution 179ms
Transfer 143 KB
Unused 55%
Monthly Cost $2/mo
www.ucar.edu
Other
Optional
Execution 93ms
Transfer 11 KB
Monthly Cost $1/mo
Microsoft Clarity
Session Replay
Optional
Execution 51ms
Transfer 25 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

55% of www.ucar.edu's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

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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