aqicn.org

Readiness by lane

Green: aqicn.org. Thin bar: Weather Forecast peer median.

Priority fixes for aqicn.org

Ordered by impact and by how common each practice is among peers.

1. Priority 1 · Harden

   Certificate has more than 14 days left

   Observed: The certificate from Let's Encrypt was due to expire on 2026-11-01 (9 days after the check).

   Why it matters: An expired certificate makes browsers show a full-page warning. Renewing well ahead of expiry leaves time to fix a failed renewal.

   What to do: Automate renewal with ACME (for example Let's Encrypt or your CDN's managed certificates) and add a renewal review to your release calendar so any certificate inside 21 days of expiry gets attention.

   99% of Weather Forecast peers do this. Limit: Certificate and protocol were observed from one vantage point; CDNs can present different certificates by region.

   Guide: HTTPS and TLS Guide for Website Owners

2. Priority 2 · Harden

   TLS 1.3 negotiated

   Observed: The TLS connection negotiated TLSv1.2.

   What to do: Enable TLS 1.3 on your CDN or server. Keep TLS 1.2 available for older clients unless you have checked your audience.

   88% of Weather Forecast peers do this.

   Guide: HTTPS and TLS Guide for Website Owners

3. Priority 3 · Harden

   HSTS kept for at least a year

   Observed: Strict-Transport-Security was sent with a max-age of 0 days, below the one-year benchmark.

   What to do: Send Strict-Transport-Security on HTTPS responses. Start with a short max-age (for example 300 seconds), confirm every subdomain works over HTTPS, then raise it in steps to 31536000. Add includeSubDomains only when all subdomains are HTTPS. HSTS preload is optional and hard to undo; hstspreload.org itself does not recommend it by default.

   39% of Weather Forecast peers do this.

   Guide: HTTPS and TLS Guide for Website Owners

4. Priority 4 · Accelerate

   Static files cached for 30 days or more

   Observed: A same-site stylesheet or script was cacheable for 1 days, short of the 30-day benchmark.

   What to do: Give versioned (fingerprinted) CSS, JavaScript, fonts and images Cache-Control: public, max-age=31536000, immutable, and change the file name whenever the content changes.

   48% of Weather Forecast peers do this.

   Guide: Browser Caching Guide for Website Owners

What aqicn.org already does well

Practices fewer than half of Weather Forecast peers use.

• Modern image formats in useWebP or AVIF images detected.23% of peers
• Reachable over IPv6IPv6 address published.48% of peers

What we saw

Homepage checked

https://aqicn.org/

Homepage response

HTTP 200, after 1 redirect

TLS

TLSv1.2, HTTP/2

Certificate

Let's Encrypt, 89-day validity, expiring 2026-11-01

DNS operators

Linode/Akamai DNS

HSTS

max-age 0 days

DMARC policy

p=none

Homepage HTML

206 KB, gzip

Images on homepage

49 (png 27, jpg 4, webp 1)

Limits: homepage only, one location, one moment. Header checks reflect the homepage response; other pages may differ.

Stack and providers

Seen in the homepage response, certificate and DNS. Provider pages compare how their customers configure the same checks.

All 31 checks

Select a gap for the method and fix. How each check works

Compare with other Weather Forecast sites

• aemet.es44
• lamma.toscana.it43
• meteoam.it46
• metservice.com46
• vremea.net46

Weather Forecast readiness benchmark