Google Weather API (Maps Platform) vs NOAA National Weather Service API (api.weather.gov)

Google Weather API (Maps Platform)

Covered by the Maps Platform SLA, 99.9 per cent with service credits. History is 24 hours only, and bulk data isn't available.

NOAA National Weather Service API (api.weather.gov)

Free, no key and no account, with public domain data. US and territories only.

Google Weather API (Maps Platform)

1. Ask for only the days or hours you need, one location a call. Every call is one billable event
2. Page with pageSize and pageToken rather than asking for 240 hours at once
3. Check the coverage page before promising alerts. Coverage is by country
4. Refetch rather than cache. The Maps terms give no caching window for weather content
5. Restrict the key to the Weather API and your server IPs in the Cloud console

NOAA National Weather Service API (api.weather.gov)

1. Set User-Agent to your app name and a contact email or the request is refused with 403
2. Cache the /points response per coordinate. The office and grid rarely change
3. Round coordinates to four decimal places. More precision returns an error
4. Don't add cache-busting query parameters. Unknown parameters return 400
5. Back off about five seconds after a throttled request and reuse the last good response