National Weather Service United States Department of Commerce

Gridpoint Frequently Asked Questions

What’s a gridpoint?

Each National Weather Service forecast office issues numerical forecasts on a 2.5-kilometer grid across their entire forecast area. Each gridpoint is one of these 2.5km squares.

The /gridpoints endpoint in the API gives you access to this raw numerical data.

How do I determine the gridpoint for my location?

You can retrieve the metadata for a given latitude/longitude coordinate with the /points endpoint ({lat},{lon}).

The forecastGridData property will provide a link to the correct gridpoint for that location.

Can I search by city or airport instead?

Please see our FAQ about geocoding.

How is the gridpoint data formatted?

What layer data is available?

Below is a list of layers that the API exposes.

Commonly used layers
Other layers

How can I tell if the grid data has been updated?

The API supports HTTP conditional requests. All gridpoint endpoints will include a Last-Modified header showing the creation time of the grid data we received from the forecast office. You may include this time in the If-Modified-Since header on subsequent requests to determine if the data has been updated. If it has not, you will receive a 304 (Not Modified) response.

If your HTTP client cannot support conditional requests for some reason, this information is also in the updateTime property of the gridpoint data.

I see some really strange values (like temperatures in the thousands).

Please report this as an operational issue.