Daymet V4: Daily Surface Weather and Climatological Summaries

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climate daily daylight flux geophysical nasa ornl precipitation radiation snow temperature vapor water weather


Daymet V4 provides gridded estimates of daily weather parameters for Continental North America, Hawaii, and Puerto Rico (Data for Puerto Rico is available starting in 1950). It is derived from selected meteorological station data and various supporting data sources.

Compared to the previous version, Daymet V4 provides effective solutions to known issues and further considers improvements to what were believed to be input weather station biases. Improvements include:

  • Reductions in the timing bias of input reporting weather station measurements.

  • Improvement to the three-dimensional regression model techniques in the core algorithm.

  • A novel approach to handling high elevation temperature measurement biases.

2020 and 2021 data are ingested from V4 R1 sources



1000 meters


Name Units Min Max Description
dayl seconds 0* 86400*

Duration of the daylight period. Based on the period of the day during which the sun is above a hypothetical flat horizon.

prcp mm 0* 544*

Daily total precipitation, sum of all forms converted to water-equivalent.

srad W/m^2 0* 1051*

Incident shortwave radiation flux density, taken as an average over the daylight period of the day.

swe kg/m^2 0* 13931*

Snow water equivalent, the amount of water contained within the snowpack.

tmax °C -60* 60*

Daily maximum 2-meter air temperature.

tmin °C -60* 42*

Daily minimum 2-meter air temperature.

vp Pa 0* 8230*

Daily average partial pressure of water vapor.

* estimated min or max value

Terms of Use

Terms of Use

This dataset is in the public domain and is available without restriction on use and distribution. See NASA's Earth Science Data & Information Policy for additional information.


  • Thornton, M.M., R. Shrestha, Y. Wei, P.E. Thornton, S-C. Kao, and B.E. Wilson. 2022. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 4 R1. ORNL DAAC, Oak Ridge, Tennessee, USA.

  • Other Citation Details - Thornton, M.M., R. Shrestha, Y. Wei, P.E. Thornton, S. Kao, and B.E. Wilson. 2020. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 4. ORNL DAAC, Oak Ridge, Tennessee, USA. doi:10.3334/ORNLDAAC/1840


Explore with Earth Engine

Code Editor (JavaScript)

var dataset = ee.ImageCollection('NASA/ORNL/DAYMET_V4')
                  .filter('2017-04-01', '2017-04-30'));
var maximumTemperature ='tmax');
var maximumTemperatureVis = {
  min: -40.0,
  max: 30.0,
  palette: ['1621A2', 'white', 'cyan', 'green', 'yellow', 'orange', 'red'],
Map.setCenter(-110.21, 35.1, 4);
Map.addLayer(maximumTemperature, maximumTemperatureVis, 'Maximum Temperature');
Open in Code Editor