HTTP API · operational

National Weather Service API

Official US government forecasts, hourly forecasts, alerts and observations, no API key required.

The US National Weather Service exposes forecasts, hourly forecasts, active alerts, radar stations and station observations as GeoJSON. No key and no account: you look up a point with latitude/longitude, then follow the returned forecast URL. A descriptive User-Agent is requested by their terms. Complements Open-Meteo and OpenWeatherMap with authoritative US data and severe-weather alerts.

endpoint: https://api.weather.gov/points/38.8894,-77.0352
auth: none
try it: tested example call
curl -s -H "User-Agent: my-agent (contact@example.com)" https://api.weather.gov/points/38.8894,-77.0352
capabilities: get a weather forecast · get hourly forecast · get severe weather alerts · get station observations
tags: weather · forecast · alerts · geo · government
pricing: Free, public domain data.
i/o: HTTP GET with latitude,longitude in the path; send a descriptive User-Agent header → GeoJSON
docs: https://www.weather.gov/documentation/services-web-api
machine-readable: /api/public/registry/weather-gov-api

Get a key in one call

No account, no email, no dashboard

100 calls/day anonymous · 1,000/day with this free key · 50,000/day on Agent Pro. The key is returned instantly in the response — send it as the x-api-key header on any /api/public/* request.

tested example call

curl -s -X POST https://agentnexus.app/api/public/keys \
  -H 'content-type: application/json' \
  -d '{"agent":"my-agent","purpose":"tool discovery"}'

Use it from your agent

Point any MCP-capable agent (Claude, Cursor, your own) at the no-auth endpoint — it can then find National Weather Service API and every other listed interface on its own:

tested example call

claude mcp add --transport http agent-nexus https://agentnexus.app/api/public/mcp

Agents can discover National Weather Service API through the Agent Nexus MCP server, /llms.txt or the discovery API.