jma.go.jp

Readiness by lane

Green: jma.go.jp. Thin bar: Weather Forecast peer median.

Priority fixes for jma.go.jp

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

1. Priority 1 · Enable

   robots.txt published

   Observed: No robots.txt file was returned at the site root.

   Why it matters: robots.txt is where crawlers look first for crawl rules and sitemap locations. Without it, they assume everything is open.

   What to do: Publish /robots.txt with any crawl rules you need and a Sitemap: line pointing to your XML sitemap.

   90% of Weather Forecast peers do this. Limit: Only the standard location was requested, once, at the time of the check.

   Guide: Robots.txt Guide: Control Crawling Without Hiding Mistakes

2. Priority 2 · Accelerate

   Static files cached for 30 days or more

   Observed: A same-site stylesheet or script was cacheable for 600 seconds, 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

3. Priority 3 · Enable

   XML sitemap discoverable

   Observed: No sitemap was listed in robots.txt or found at /sitemap.xml.

   What to do: Generate an XML sitemap of canonical URLs, reference it in robots.txt and submit it in Google Search Console.

   66% of Weather Forecast peers do this.

   Guide: XML Sitemap Guide: Include Only URLs You Stand Behind

4. Priority 4 · Accelerate

   No render-blocking scripts in <head>

   Observed: The homepage <head> loaded 5 external scripts without async or defer.

   What to do: Add defer to scripts that need the DOM, async to independent ones such as analytics, or move them to the end of the body.

   56% of Weather Forecast peers do this.

   Guide: Control Third-Party Scripts Before They Control Your Page

What jma.go.jp already does well

Practices fewer than half of Weather Forecast peers use.

• Content Security Policy presentContent-Security-Policy present.22% of peers
• Referrer-Policy setReferrer-Policy present.27% of peers
• Framing restrictedFraming controls present.38% of peers

What we saw

Homepage checked

https://www.jma.go.jp/

Homepage response

HTTP 200, after 1 redirect

TLS

TLSv1.3, HTTP/2

Certificate

GlobalSign, 199-day validity, expiring 2027-03-05

CDN or edge

Amazon CloudFront

DNS operators

Amazon Route 53

HSTS

max-age 365 days, preload

DMARC policy

p=none

Homepage HTML

15 KB, gzip

Images on homepage

22 (png 11, jpg 5, svg 5, gif 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

• donnerwetter.de52
• meteocentrum.cz54
• meteociel.fr53
• twojapogoda.pl54
• willyweather.com.au54

Weather Forecast readiness benchmark