Measured US snow, rain, hail and aurora totals by state and city.
WeatherTotals API is a free Weather API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
Get WeatherTotals figures as JSON, free, no key or signup. Same numbers as the pages, updated every 5 to 60 minutes. CORS open for browser calls.
Details from weathertotals.com.

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Current weather, local time, UTC offset and DST rules for 400 cities as static JSON
The WeatherTotals API is provided by WeatherTotals (weathertotals.com). Get WeatherTotals figures as JSON, free, no key or signup. Same numbers as the pages, updated every 5 to 60 minutes. CORS open for browser calls.
Yes. The WeatherTotals API is listed in the Weather category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The WeatherTotals API requires no authentication, so you can start making requests without signing up.
Yes. The WeatherTotals API supports CORS, so front-end JavaScript can call it directly.
Yes. The WeatherTotals API is served over HTTPS, so it's safe to use in production.