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NWS Transformation
Multiple Days of Severe Weather from Thunderstorms and Wildfires
Active spring pattern across the center of the nation with several rounds of severe thunderstorms in the forecast through the weekend. The regions under the greatest threats are the southern Plains into the Mississippi Valley. Meanwhile, dry and breezy conditions with dry fuels are aiding in wildfires across the western High Plains and the Southeast. Wind and some snow for northern Rockies.
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Overview
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Specification
Overview
The National Weather Service (NWS) API allows developers access to critical forecasts, alerts, and observations, along with other weather data. The API was designed with a cache-friendly approach that expires content based upon the information life cycle. The API is based upon of
JSON-LD
to promote machine data discovery.
The API is located at:
Operational issues should be reported to
nco.ops@noaa.gov
General use questions can be asked on
the API github site
Pricing
All of the information presented via the API is intended to be open data, free to use for any purpose. As a public service of the United States Government, we do not charge any fees for the usage of this service, although there are reasonable rate limits in place to prevent abuse and help ensure that everyone has access. The rate limit is not public information, but allows a generous amount for typical use. If the rate limit is execeed a request will return with an error, and may be retried after the limit clears (typically within 5 seconds). Proxies are more likely to reach the limit, whereas requests directly from clients are not likely.
Content Negotiation
The new API will use headers to modify the version and format of the response. Every request, either by browser or application, sends header information every time you visit any website. For example, a commonly used header called "UserAgent" tells a website what type of device you are using so it can tailor the best experience for you. No private information is shared in a header, and this is a standard practice for all government and private sites. Developers can override these headers for specific purposes (see the "API Specifications" tab for more information). You can get full details by visiting the header field definitions page at the
World Wide Web Consortium
site.
Authentication
Format the response
Request new features
Authentication
A User Agent is required to identify your application. This string can be anything, and the more unique to your application the less likely it will be affected by a security event. If you include contact information (website or email), we can contact you if your string is associated to a security event. This will be replaced with an API key in the future.
User-Agent: (myweatherapp.com, contact@myweatherapp.com)
Formats
Endpoints typically have a GeoJSON default format, given the inclusion of geometry data. See the Specification tab for details on each endpoint. Below are common formats available by the API.
GeoJSON:
application/geo+json
JSON-LD:
application/ld+json
DWML:
application/vnd.noaa.dwml+xml
OXML:
application/vnd.noaa.obs+xml
CAP:
application/cap+xml
ATOM:
application/atom+xml
Accept: application/cap+xml
Features
The API will use feature flags to make new features available to consumers. The available feature flags will be noted on the "Updates" and "Specification" tabs on this page. The feature flag will be communicated through a Service Change Notice (SCN) allowing developers a period to adopt the flag if the change impacts their applications. Once the adoption window expires, the feature will be made default. Developers can then remove the flag at their convenience.
Feature-Flags: forecast_temperature_qv
Outage Information
Information on outages is generally
communicated through Administrative messages sent by National Center of Environmental Prediction's (NCEP's) Senior Duty Meteorologist (SDM)
. These are sent via WMO id NOUS42 KWNO and product identifier ADASDM.
Questions & Examples
The API uses linked data to allow applications to discover content. Similar to a web site that provides HTML links to help users navigate to each page, linked data helps applications navigate to each endpoint. You may also review the OPEN API specification on the "Specification" tab on this page, or directly using the specification endpoint (that is also used to create the tab presentation):
How do I get the forecast?
Forecasts are created at each
NWS Weather Forecast Office (WFO)
on their own grid definition, at a resolution of about 2.5km x 2.5km. The API endpoint for the 12h forecast periods at a specific grid location is formatted as:
For example: https://api.weather.gov/gridpoints/TOP/31,80/forecast
To obtain the grid forecast for a point location, use the /points endpoint to retrieve the current grid forecast endpoint by coordinates:
For example: https://api.weather.gov/points/39.7456,-97.0892
This will provide the grid forecast endpoints for three format options in these properties:
forecast
- forecast for 12h periods over the next seven days
forecastHourly
- forecast for hourly periods over the next seven days
forecastGridData
- raw forecast data over the next seven days
Note: at this time coastal marine grid forecasts are only available from the
forecastGridData
property.
Applications may cache the grid for a location to improve latency and reduce the additional lookup request; however, it is important to note that while it generally does not occur often, the gridX and gridY values (and even the office) for a given coordinate may occasionally change. For this reason, it is necessary to check back to the /points endpoint periodically for the latest office/grid mapping.
The /points endpoint also contains information about the issuing office, observation stations, and zones for a given point location.
How do I get the forecast as DWML?
The forecast can be formatted as DWML for the /forecast and /forecast/hourly endpoints. There is no DWML specification for point lookups, so you first need to use the JSON-only /point endpoint described in the previous question to convert the location to a grid. Once you know the full gridpoint url for the forecast or hourly forecast, you can set the Accept header described in the overview to request the DWML format.
application/vnd.noaa.dwml+xml
For example: https://api.weather.gov/gridpoints/TOP/31,80/forecast
How do I get alerts?
The API has a robust selection of filters for alerts. A common request is all active alerts for a state:
For example: https://api.weather.gov/alerts/active?area=KS
The /alerts/active endpoint redirects internally to the root /alerts endpoint with the "active=true" parameter. Please review the "Specification" tab above for all the filter options. For important details about filtered alerts requests according to county or zone UGC, please review our
Alerts Geolocation Guide
For additional details on the format of an alert's content, please see the
CAP documentation
The /alerts endpoint contains alerts issued over the past seven days. For an official archive of NWS CAP alerts, please reach out to the
National Centers for Environmental Information (NCEI)
Can I retrieve radar display data?
No. The radar endpoints in api.weather.gov are used for radar status data and do not contain the radar data used for display. For radar display data, consider these options:
RIDGE2 NWS Radar Display
RIDGE2 NWS Radar Data as OGC Web Services
Other NWS OGC Web Services
MRMS Data
NODD MRMS Archive Data
Updates
The information on this page is updated regularly. All official NWS Service Change Notices, including an email subscription option, can be found at
weather.gov/notification
Feature Flags
Feature flags are endpoint specific. See Specification tab for details.
/gridpoints/{wfo}/{x},{y}/forecast and /gridpoints/{wfo}/{x},{y}/forecast/hourly
forecast_temperature_qv: Represent temperature as QuantitativeValue
forecast_wind_speed_qv: Represent wind speed as QuantitativeValue
/stations, /stations/{stationId}, and /gridpoints/{wfo}/{x},{y}/stations
obs_station_provider: Show provider and subProvider MADIS details
Known Issues
Before contacting us, please review the following list of issues that have been identified for a future update.
No significant known issues.
Updated 3/24/2026
Upstream Issues/Changes
The following issues are related to upstream sources of the API, and are not an API bug.
Station observations endpoints always show missing (null) 24h max/min temperatures for stations outside the central time zone due to MADIS ingest bug.
Delayed observations
Observations may be delayed up to 20 minutes from
MADIS
, the upstream source, due to QC processing.
Resolutions
The following issues have been recently resolved:
17 Mar 2026: The /radar/queues/rds and /radar/queues/tds endpoints are limited by default so that they no longer return a 503 error from too many results.
7 Jan 2026: The /forecast and /forecast/hourly endpoints no longer contain data that has past (ex. previous hours in an hourly forecast or the words "Overnight" during the early part of the day).
15 Dec 2025: Precipitation values in the observations endpoints are rounded down to the nearest centimeter (less than 0.4" may be improperly rounded down to 0).
2 Oct 2025: Upstream MADIS bug resolved so that station observations endpoints no longer always show missing (null) wind gust values.
4 Aug 2025:
Station observations should no longer be routinely delayed more than about the 20 minutes it takes the upstream MADIS source to QC and ingest for API.
Station observations should no longer have missing (null) values for weather properties (temperature, wind, precipitation, etc.) when the MADIS source has data and
passed all QC levels
22 May 2025:
XML data requests to the stations/
/alerts/types
have been updated to correct "Evacuation Immediate" and add/remove types to align with what appears in the
Hazards Map
PoP values less than 20% in the 12h forecast endpoints (/gridpoints/{office}/{gridX},{gridY}/forecast) no longer display as null values.
Periods with extra ellipses (...) in the WFO's forecast zone text product (ZFP) are now properly displayed in the /zones/{type}/{zoneId}/forecast endpoint.
For more details on other changes with this upgrade, please see
SCN 25-44
Specification
Note:
All times generated by the API are in
ISO-8601 format
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National Oceanic and Atmospheric Administration
National Weather Service
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