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https://forecast7.com

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
92
GRADE
A
FIX
1
REVIEW
2
PASS
12
INFO
2

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

Mobile Desktop
99
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
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.

797 ms

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

797 ms

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

105 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.

797 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.

3.91 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
17
12 PASS 2 REVIEW 1 FIX
D
Third-Party Impact
Action
97% third-party, 0 ms blocking
FIX
97% third-party, 0 ms blocking
Warning::
Third-party code accounts for 97% of page weight (293.1 KiB of 303.4 KiB)
Info::
Third-party blocking time is low (0 ms)
97%
First-party Third-party
B
JS Bundles
3 scripts, 127 KB unused
REVIEW
3 scripts, 127 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=UA-342...: 64 KB unused (51%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-G2QD...: 63 KB unused (43%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 127 KB
127 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=UA-342083-4125 KB64 KB (51%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-G2QDBNZ1PY&cx=c&gtm=4e64h1146 KB63 KB (43%)✓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

B
HTTP Caching
public
REVIEW
public
Info::
Cache-Control header is set
Got: public
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

public

DirectiveValueMeaning
public—Any cache may store this response
A+
Page Weight Budget
303 KB transferred, 9 requests
PASS
303 KB transferred, 9 requests
Info::
Page weighs 850 KB (303 KB transferred)
Info::
9 HTTP requests
Info::
Estimated 0.06 g CO2 per page load
303 KB / 2.4 MB budget
303 KB transferred
9 requests
0.06 g CO2 per page load
JavaScript 292.6 KiB 96%
CSS 4.1 KiB 1%
Images 2.1 KiB 1%
HTML 2.0 KiB 1%
Other 1.4 KiB 0%
Other 705 B 0%
Other 547 B 0%
0 2.4 MB 4.9 MB
Under budget
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
1 images, 0 KB saveable
PASS
1 images, 0 KB saveable
Warning::
https://forecast7.com/img/forecast7-big.svg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
1 images 2 KB
0 oversized -0 KB
1 legacy format
1 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

A+
JS Execution Cost
440ms total JS execution
PASS
440ms total JS execution
Info::
Unattributable: 176ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=G-G2QD...: 135ms CPU time
Info::
https://www.googletagmanager.com/gtag/js?id=UA-342...: 130ms CPU time
Warning::
Third-party scripts: 440ms (100% of total)

Main Thread Breakdown

Script Evaluation 57% Other 23% Script Parsing & Compilation 12% Style & Layout 5%
ScriptTotalScriptingParse/CompileParty
Unattributable176ms54ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-G2QDBNZ1PY&cx=c&gtm=4e64h1135ms103ms31ms3rd
https://www.googletagmanager.com/gtag/js?id=UA-342083-4130ms102ms26ms3rd
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
A
Page Weight Inventory
9 resources · 303 KB · 127 KB savings available
PASS
9 resources · 303 KB · 127 KB savings available
Info::
Within 1MB page-weight target
Got: 303 KB
Info::
~127 KB of savings available
Warning::
4 third-party resources (97% of weight)
9 resources · 303.4 KiB · 4 third-party Within 1MB page-weight target
JavaScript 96% · 292.6 KiB
CSS 1% · 4.1 KiB
Image 1% · 3.6 KiB
Document 1% · 2.0 KiB
Other 0% · 1.2 KiB

~126.7 KiB of savings available

Remove unused JavaScript: 126.7 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
9 requests over 462ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 797 ms LCP 797 mshttps://forecast7.com// https://forecast7.com/ — 200 — 2.0 KiB — 68 ms — h2https://www.googletagmanager.com/gtag/js?id=UA-342083-4www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=UA-342083-4 — 200 — 125.3 KiB — 167 ms — h2https://forecast7.com/css/styles.css?v=17/css/styles.css?v=17 https://forecast7.com/css/styles.css?v=17 — 200 — 4.1 KiB — 24 ms — h2https://forecast7.com/img/forecast7-big.svg/img/forecast7-big.svg https://forecast7.com/img/forecast7-big.svg — 200 — 2.1 KiB — 25 ms — h2https://forecast7.com/manifest.json/manifest.json https://forecast7.com/manifest.json — 200 — 705 B — 44 ms — h3https://www.googletagmanager.com/gtag/js?id=G-G2QDBNZ1PY&cx=c&gtm=4e64h1www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-G2QDBNZ1PY&cx=c&gtm=4e64h1 — 200 — 146.3 KiB — 54 ms — h2https://www.google-analytics.com/analytics.jswww.google-analytics.com/analytics.... https://www.google-analytics.com/analytics.js — 200 — 20.9 KiB — 99 ms — h2https://region1.google-analytics.com/g/collect?v=2&tid=G-G2QDBNZ1PY&gtm=45je64h1v9132614311za20g&_p=1776820103401&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&_eu=EAAI&are=1&cid=1848073732.1776820104&frm=0&ir=1&pscdl=noapi&rcb=0&sr=412x823&uaa=&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938466~115938469~117266400~117512542~117884344&sid=1776820103&sct=1&seg=0&dl=https%3A%2F%2Fforecast7.com%2F&dt=Forecast7.com%20-%20Weather%20Forecast&en=page_view&_fv=1&_nsi=1&_ss=1&tfd=392region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-G2QDBNZ1PY&gtm=45je64h1v9132614311za20g&_p=1776820103401&gcd=13l3l3l2l1l1&npa=1&dma_cps=a&dma=1&_eu=EAAI&are=1&cid=1848073732.1776820104&frm=0&ir=1&pscdl=noapi&rcb=0&sr=412x823&uaa=&uab=64&uafvl=Chromium%3B147.0.7727.101%7CNot.A%252FBrand%3B8.0.0.0&uam=moto%20g%20power%20(2022)&uamb=1&uap=Android&uapv=11.0&uaw=0&ul=en-us&_s=1&tag_exp=0~115938466~115938469~117266400~117512542~117884344&sid=1776820103&sct=1&seg=0&dl=https%3A%2F%2Fforecast7.com%2F&dt=Forecast7.com%20-%20Weather%20Forecast&en=page_view&_fv=1&_nsi=1&_ss=1&tfd=392 — 204 — 547 B — 70 ms — h2https://forecast7.com/favicon-32x32.png/favicon-32x32.png https://forecast7.com/favicon-32x32.png — 200 — 1.4 KiB — 29 ms — h3
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 440ms · 272KB · $6/mo
Unattributable
Other
Optional
Execution 176ms
Transfer 0 KB
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 135ms
Transfer 146 KB
Unused 43%
Monthly Cost $2/mo
Google Tag Manager
Tag Manager
Optional
Execution 130ms
Transfer 125 KB
Unused 51%
Monthly Cost $2/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

51% of Google Tag Manager'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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