noaa-weather

NOAA Weather.gov API

The National Weather Service (NWS) API provides free, open access to weather forecasts, alerts, observations, radar data, and more for the United States. All data is public domain — no API key or account required.

Always check the official API documentation and OpenAPI spec for the latest endpoint details.

Base URL

https://api.weather.gov

Authentication

No API key is needed. However, a User-Agent header is required on every request to identify your application.

User-Agent: (myweatherapp.com, contact@myweatherapp.com)

The string can be anything — the more unique to your application, the less likely it will be affected by a security event. Requests without a User-Agent may be blocked.

Key Concepts

Term	Description
Point	A latitude/longitude coordinate. Use `/points/{lat},{lon}` to resolve it to grid and zone info.
Gridpoint	A 2.5km forecast grid cell identified by a WFO office ID and x,y coordinates.
WFO	Weather Forecast Office — the NWS office responsible for a geographic area (e.g., `DEN`, `OKX`, `LOT`).
Zone	A geographic area used for forecasts and alerts. Types include `land`, `marine`, `forecast`, `fire`, `county`.
Station	An observation station (e.g., `KDEN` for Denver International Airport) that reports current conditions.
Alert	A weather warning, watch, or advisory issued by the NWS (e.g., tornado warning, winter storm watch).
SIGMET/AIRMET	Aviation weather advisories for significant or airmen's meteorological conditions.
TAF	Terminal Aerodrome Forecast — aviation weather forecast for an airport.
GeoJSON	The default response format — standard JSON with geographic feature geometry.

Core Workflow: Get a Forecast for a Location

The API uses a two-step pattern to get a forecast:

Step 1: Resolve coordinates to a grid point

GET /points/{latitude},{longitude}

This returns metadata including the WFO office, grid coordinates, and URLs for forecasts.

Step 2: Fetch the forecast using the grid info

GET /gridpoints/{wfo}/{gridX},{gridY}/forecast

This returns the human-readable 12-hour period forecast (7 days).

Example (curl)

# Step 1: Get grid info for Denver, CO
curl -s -H "User-Agent: MyApp" \
  "https://api.weather.gov/points/39.7456,-104.9994" | jq '.properties.forecast'

# Returns: "https://api.weather.gov/gridpoints/BOU/63,62/forecast"

# Step 2: Get the forecast
curl -s -H "User-Agent: MyApp" \
  "https://api.weather.gov/gridpoints/BOU/63,62/forecast" | jq '.properties.periods[0]'

Endpoint Reference

Points / Location Lookup

Endpoint	Description
`GET /points/{lat},{lon}`	Metadata for a coordinate — returns grid info, forecast URLs, timezone, county, zone
`GET /points/{lat},{lon}/stations`	Nearby observation stations (deprecated — use gridpoint stations instead)

Forecasts

Endpoint	Description
`GET /gridpoints/{wfo}/{x},{y}/forecast`	12-hour period forecast (7-day), human-readable
`GET /gridpoints/{wfo}/{x},{y}/forecast/hourly`	Hourly forecast (7-day), human-readable
`GET /gridpoints/{wfo}/{x},{y}`	Raw numerical forecast data (temperature, wind, precip probability, etc.)
`GET /gridpoints/{wfo}/{x},{y}/stations`	Observation stations within the grid area

Alerts

Endpoint	Description
`GET /alerts`	Query alerts (past 7 days) with filters: `status`, `event`, `area`, `zone`, `urgency`, `severity`, `certainty`
`GET /alerts/active`	All currently active alerts
`GET /alerts/active/count`	Count of active alerts by area, zone, and region
`GET /alerts/active/zone/{zoneId}`	Active alerts for a specific zone
`GET /alerts/active/area/{area}`	Active alerts for a state (2-letter code) or marine area
`GET /alerts/active/region/{region}`	Active alerts for a marine region
`GET /alerts/types`	List of recognized alert event types
`GET /alerts/{id}`	Retrieve a specific alert by its ID

Stations & Observations

Endpoint	Description
`GET /stations`	List observation stations; filter by `id`, `state`, `limit`
`GET /stations/{stationId}`	Metadata for a specific station
`GET /stations/{stationId}/observations`	Historical observations (paginated)
`GET /stations/{stationId}/observations/latest`	Most recent observation
`GET /stations/{stationId}/observations/{time}`	Observation at a specific ISO-8601 timestamp

Zones

Endpoint	Description
`GET /zones`	Query zones; filter by `id`, `area`, `type`, `point`, `include_geometry`
`GET /zones/{type}`	List zones of a specific type (`land`, `marine`, `forecast`, `fire`, `county`)
`GET /zones/{type}/{zoneId}`	Metadata for a specific zone
`GET /zones/{type}/{zoneId}/forecast`	Current text forecast for a zone
`GET /zones/forecast/{zoneId}/observations`	Observations within a forecast zone
`GET /zones/forecast/{zoneId}/stations`	Stations within a forecast zone

Aviation

Endpoint	Description
`GET /stations/{stationId}/tafs`	Terminal Aerodrome Forecasts for a station
`GET /stations/{stationId}/tafs/{date}/{time}`	Specific TAF
`GET /aviation/cwsus/{cwsuId}`	Center Weather Service Unit metadata
`GET /aviation/cwsus/{cwsuId}/cwas`	Center Weather Advisories
`GET /aviation/sigmets`	Query SIGMETs/AIRMETs with filters
`GET /aviation/sigmets/{atsu}`	SIGMETs for a specific ATSU
`GET /aviation/cwsus/{cwsuId}/cwas/{date}/{sequence}`	Specific Center Weather Advisory
`GET /aviation/sigmets/{atsu}/{date}/{time}`	Specific SIGMET by date and time

Radar

Endpoint	Description
`GET /radar/servers`	List of radar servers
`GET /radar/stations`	List of radar stations; filter by `stationType`, `host`
`GET /radar/stations/{stationId}`	Specific radar station metadata
`GET /radar/stations/{stationId}/alarms`	Alarms for a radar station
`GET /radar/profilers/{stationId}`	Wind profiler data

Text Products

Endpoint	Description
`GET /products`	Query text products; filter by `location`, `type`, `start`, `end`
`GET /products/{productId}`	Specific text product
`GET /products/types`	List of valid product type codes
`GET /products/locations`	List of valid product issuance locations
`GET /products/types/{typeId}`	Products of a given type
`GET /products/types/{typeId}/locations`	Issuance locations for a product type
`GET /products/locations/{locationId}/types`	Product types for a location
`GET /products/types/{typeId}/locations/{locationId}`	Products by type and location
`GET /products/types/{typeId}/locations/{locationId}/latest`	Latest product by type and location

Offices

Endpoint	Description
`GET /offices/{officeId}`	NWS forecast office metadata
`GET /offices/{officeId}/headlines`	News headlines from an office
`GET /offices/{officeId}/headlines/{headlineId}`	Specific headline
`GET /offices/{officeId}/briefing`	Active office briefing
`GET /offices/{officeId}/weatherstories`	Active weather stories

Miscellaneous

Endpoint	Description
`GET /glossary`	Weather terminology definitions
`GET /points/{lat},{lon}/radio`	NOAA Weather Radio script for a location
`GET /radio/{callSign}/broadcast`	Weather Radio broadcast script by call sign

Response Format

The default response format is GeoJSON (application/geo+json). Control the format with the Accept header:

Format	Accept Header
GeoJSON (default)	`application/geo+json`
JSON-LD	`application/ld+json`
DWML (XML)	`application/vnd.noaa.dwml+xml`
CAP (Alerts XML)	`application/cap+xml`
OXML (Observations XML)	`application/vnd.noaa.obs+xml`
ATOM	`application/atom+xml`

All times are in ISO-8601 format.

Feature Flags

Optional headers to enable new features:

Header Value	Description
`Feature-Flags: forecast_temperature_qv`	Represent temperature as QuantitativeValue
`Feature-Flags: forecast_wind_speed_qv`	Represent wind speed as QuantitativeValue
`Feature-Flags: obs_station_provider`	Show MADIS provider details for stations

Code Examples

Get Forecast for a Location (Python)

import requests

BASE = "https://api.weather.gov"
HEADERS = {"User-Agent": "(myapp, contact@example.com)"}

# Step 1: Resolve coordinates
point = requests.get(f"{BASE}/points/39.7456,-104.9994", headers=HEADERS).json()
forecast_url = point["properties"]["forecast"]

# Step 2: Get forecast
forecast = requests.get(forecast_url, headers=HEADERS).json()
for period in forecast["properties"]["periods"][:4]:
    print(f"{period['name']}: {period['detailedForecast']}")

Get Active Alerts for a State (curl)

curl -s -H "User-Agent: MyApp" \
  "https://api.weather.gov/alerts/active?area=CO" \
  | jq '.features[] | {event: .properties.event, headline: .properties.headline}'

Get Current Observations (curl)

# Get latest observation from Denver International Airport
curl -s -H "User-Agent: MyApp" \
  "https://api.weather.gov/stations/KDEN/observations/latest" \
  | jq '.properties | {
    temperature: .temperature.value,
    windSpeed: .windSpeed.value,
    description: .textDescription
  }'

Get Hourly Forecast (Node.js)

const https = require("https");

const options = {
  headers: { "User-Agent": "MyApp (contact@example.com)" },
};

// Step 1: Get grid info
https.get("https://api.weather.gov/points/40.7128,-74.0060", options, (res) => {
  let data = "";
  res.on("data", (chunk) => (data += chunk));
  res.on("end", () => {
    const forecastUrl = JSON.parse(data).properties.forecastHourly;

    // Step 2: Get hourly forecast
    https.get(forecastUrl, options, (res2) => {
      let forecast = "";
      res2.on("data", (chunk) => (forecast += chunk));
      res2.on("end", () => {
        const periods = JSON.parse(forecast).properties.periods;
        periods.slice(0, 6).forEach((p) => {
          console.log(`${p.startTime}: ${p.temperature}°${p.temperatureUnit} - ${p.shortForecast}`);
        });
      });
    });
  });
});

Find Nearby Stations (Python)

import requests

BASE = "https://api.weather.gov"
HEADERS = {"User-Agent": "(myapp, contact@example.com)"}

# Get grid info for a point
point = requests.get(f"{BASE}/points/34.0522,-118.2437", headers=HEADERS).json()
stations_url = point["properties"]["observationStations"]

# List nearby stations
stations = requests.get(stations_url, headers=HEADERS).json()
for station in stations["features"][:5]:
    props = station["properties"]
    print(f"{props['stationIdentifier']}: {props['name']}")

Rate Limits

The rate limit is not publicly documented but is described as "generous for typical use."

Guideline	Details
Rate limit	Undisclosed, but generous
On limit exceeded	Request returns an error; retry after ~5 seconds
User-Agent	Required — requests without it may be blocked
Best practice	Cache `/points` responses (they rarely change) to reduce calls

Error Handling

HTTP Status	Meaning	Action
200	Success	Parse the JSON response
301/302	Redirect	Follow the redirect
404	Not found	Check coordinates, station ID, or zone ID
500	Server error	Retry with backoff
503	Service unavailable	Common on `/radar/queues` — add filters to reduce results

Error responses include a JSON body with type, title, status, detail, and correlationId fields.

Known Issues

/radar/queues endpoints may return 503 errors when results are large — filter with additional parameters.
Station observations outside the central timezone may show null 24-hour max/min temperatures.
Observation data can be delayed up to 20 minutes from the upstream MADIS source.
Icon endpoints (/icons) are deprecated.

Resources

Resource	URL
API Documentation	weather.gov/documentation/services-web-api
OpenAPI Specification	api.weather.gov/openapi.json
GitHub Discussion	weather-gov.github.io/api
Operational Support	nco.ops@noaa.gov

Changelog

0.1.0 — Initial release with forecasts, alerts, observations, stations, zones, aviation, radar, and text products.