NOAA Weather Forecast & Alerts (Official API)

US weather forecasts and active severe weather alerts, straight from the National Weather Service API. No scraping, no API key.

Two modes

Forecast by coordinates — give one or more US points and get the official NWS forecast: daily periods (about 14) or hourly (about 156), with temperature, wind, precipitation probability and the forecaster's own wording.

Active alerts — every alert currently in effect, filtered by state, severity, urgency or event type: flood warnings, tornado watches, winter storm warnings, heat advisories.

Why this Actor

• Official API only. Calls api.weather.gov. No HTML scraping, no third-party weather site.
• No API key. NWS publishes this openly.
• Public domain. U.S. government works, free to use and redistribute.
• Flat rows. Nested values such as precipitation probability are unwrapped into plain columns.
• Correct by construction. NWS needs a two-step lookup (coordinates → grid → forecast); this Actor does it for you.

Required: your contact

NWS asks automated clients to identify themselves. Put your name and email in the Your contact input, for example Jane Doe jane@example.com. It is sent in the User-Agent header, as NWS requests. The Actor refuses to run without it.

Output — forecast mode

Field	Description
latitude, longitude, city, state	The point, and the place NWS matched it to
gridId, timeZone	NWS forecast office and local time zone
periodNumber, periodName	e.g. 1, "Tonight", "Saturday"
startTime, endTime	ISO timestamps with local offset
isDaytime	Day or night period
temperature, temperatureUnit, temperatureTrend	e.g. 59, "F", "falling"
precipitationProbability	Percent, unwrapped to a plain number
windSpeed, windDirection	e.g. "13 mph", "NW"
shortForecast, detailedForecast	NWS wording, short and long

Output — alerts mode

Field	Description
alertId, event	Identifier and event name, e.g. "Flood Warning"
severity, urgency, certainty, status	NWS classification
areaDesc	Counties or zones covered
headline, description, instruction	The alert text and what to do
senderName	Issuing office
effective, onset, expires, ends	Timing

Examples

Hourly forecast for two cities, 24 periods each:

{
  "mode": "forecast",
  "coordinates": ["38.8894,-77.0352", "47.6062,-122.3321"],
  "hourly": true,
  "periods_per_point": 24
}

Severe alerts in Texas:

{
  "mode": "alerts",
  "area": "TX",
  "severity": "Severe"
}

Use cases

• Operations and logistics — reroute around storms, plan crews around forecast windows
• Insurance and claims — capture what was forecast and warned before an event
• Agriculture and energy — temperature and precipitation series for specific sites
• Media and alerting — feed active warnings into your own notification system
• Research — build a forecast history by running on a schedule

Limits worth knowing

• US only. NWS covers the United States and its territories. Coordinates outside that range return a clear error rather than empty data.
• Alerts are currently active ones. Historical alerts are a different NWS endpoint.
• NWS does not support a server-side row limit on active alerts, so this Actor fetches the filtered set and trims it. Narrow with area or severity to keep runs small.

Running locally

pip install -r requirements.txt
NWS_USER_AGENT="Your Name you@example.com" python -m tests.test_noaa

Attribution

Data from the National Weather Service, NOAA, U.S. Department of Commerce. This Actor is not affiliated with or endorsed by NOAA or the NWS. For life-safety decisions, always consult the official NWS sources directly.