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NWS Public Alerts (CAP/ATOM Feeds via api.weather.gov)

NWS Public Alerts (CAP/ATOM Feeds via api.weather.gov) is a rss feed from NOAA / National Weather Service providing weather data. The U.S. National Weather Service publishes all active watches, warnings, and advisories as machine-readable feeds. ATOM index feeds (and CAP v1.2 / JSON-LD products) list active alerts by zone, county, state, point, or marine area and update in near real time. A Polymarket bot can poll these to catch heat advisories, excessive-heat warnings, winter-storm and severe-weather alerts that move NWS-temperature and weather markets.

At a glance

ProviderNOAA / National Weather Service
TypeRSS Feed
CategoryWeather
Real-timeNo — request/response
AuthNone — open endpoint
PricingFree (U.S. government public service; no API key; descriptive User-Agent header required) — Free: all alerts/forecast/observation endpoints, no account or API key, Self-identifying User-Agent header required (app name + contact email), Rate-limiting firewalls auto-throttle abuse; recommended polling no more than once per ~30s (alerts) / use HTTP cache headers

What data it provides

  • Active watches/warnings/advisories (severe storm, heat, excessive heat, winter storm, etc.)
  • Alert event type, severity, certainty, urgency, onset/expiry times
  • Affected geography: NWS forecast zones, counties (SAME/UGC codes), states, marine areas
  • ATOM index of active CAP messages for near-real-time tracking
  • Full CAP v1.2 XML alert message per event (headline, description, instructions)
  • Filtering params: ?area, ?zone, ?point=lat,lon, ?region, ?status, ?event

Features

  • Multiple formats: ATOM index, CAP v1.2 XML, and JSON-LD (default) from api.weather.gov/alerts
  • Near-real-time refresh (alerts publish on issuance; ATOM indexes updated continuously)
  • Geographic filtering by zone/county/state/point/marine area/region
  • Free with no API key; only a descriptive User-Agent header is required
  • Rate-limiting firewalls; guidance to request no more than ~every 30s and not cache-bust
  • Nationwide U.S. coverage across all NWS offices and product types

Links

Use it in a bot

Other weather data sources

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