Access to Daymet data is available from specialized tools, web services, and direct downloads allowing a rich resource of both point and gridded daily surface meteorological data and climatological summaries. The way in which a user accesses the data will depend on their needs. Each is described in more detail below. Direct links to each of the Data Access options are also provided from the Home Page.
When using Daymet data acquired from this ORNL website, please use the following citations: Data Citation/References.
Watch a NASA Earthdata Webinar: Accessing Daymet Data Through Web-Based Tools and Services.
Single Pixel Extraction
From the Single Pixel Extraction Tool, daily surface data within the Daymet database can be downloaded in tabular format for a single point. Multiple points can be automated with the Multiple Coordinates Extractor script.
This data access option allows users to enter a single geographic point by latitude and longitude in decimal degrees. A routine is executed that translates the (lon, lat) coordinates into projected Daymet (x,y) coordinates. These coordinates are used to access the Daymet database of daily interpolated surface weather variables. Daily data from the nearest 1 km x 1 km Daymet grid cell are extracted from the database and formatted as a table with one column for each Daymet variable and one row for each day. All daily data for selected years are returned as a single (long) table, formatted for display in the browser window. At the top of this table is a link to the same data in a simple text format, suitable for import into a spreadsheet or other data analysis software. Daymet variables included in the record are; for each day, maximum and minimum temperature, precipitation, shortwave radiation, water vapor pressure, snow water equivalent, and day length. Graphical Visualization plots of Daymet variables over time are also made available as shown in the image below.
Watch the segment of a NASA Earthdata Webinar explaining The Single Pixel Data Extraction Tool, Usage and Web-Based Services.
Multiple Coordinates Extractor
A script for automated data extraction at multiple locations for the Single Pixel Extraction is available for download.
Instructions for multiple location extraction:
- Unzip the attached daymet.zip onto your desktop
- Edit latlon.txt with desired location (lat lon) information
- Open command line terminal from your unzipped daymet directory
- From the command line run the following: java -Xms512m -Xmx1024m -jar daymet_multiple_extraction.jar latlon.txt
- Above program creates separate CSV files for each lat lot. All variables, all years.
Web services allowing browser viewing or CSV file download are also available for the Single Pixel Extraction Tool.
Daymet Tile Selection
The Daymet Tile Selection Tool tool provides daily data for each Daymet variable as a separate CF-compliant netCDF file. Data are downloaded in 2 degree x 2 degree tiles for selected years.
For researchers who need continuous surfaces of daily meteorologic data over study areas larger than the Single Pixel Extraction provides, Daymet data are distributed as gridded daily data in 2 degree x 2 degree tile subsets. The tile subsets are referenced by TileID, which is assigned within the Daymet algorithm. The image shows the Daymet Tiles on a Lambert Conformal Conic Projection with a subset of corresponding TileID's. The TileID is consistent throughtout all years of Daymet data.
When downloaded, the daily gridded tile data contain a tarred file of individual netCDF files for each Daymet variable: minimum and maximum temperature, precipitation, incident shortwave radiation, water vapor pressure, snow water equivalent, and day-length. The spatial resolution of the raster data is 1 km and each file is spatially referenced to the Lamber Conformal Conic projection. Example images of Daymet variables are shown below for two Daymet tiles in the Rocky Mountain West covering the northern border of Idaho and Montana. The Daymet TileIDs for these two tiles are 12273 and 12274. Recall that each netCDF file contains daily data for each Daymet variable. The images show just one day of the 365 days available in each netCDF file. Also note that these two adjacent tiles match seamlessly.
High definition animations of daily Daymet data
This animation of Maximum Temperature was created to demonstrate the daily data available from each of the netCDF files from the Daily Gridded Surface Data selection.
Download high-res animations of Daymet variables (Tmax and Prcp)
- Daily Maximum Temperature: Tile 12089_1980 (Tmax_12089_1980.zip) (190 MB)
- Daily Total Precipitation: Tile 12089_2008 (Prcp_12089_2008.zip) (70 MB)
Access to the Daymet collection of CF-NetCDF files is also available through a Thematic Real-time Environmental Distributed Data Services (THREDDS) Data server. A THREDDS data server allows users to find, access, and download data from a simple, hierarchical catalog within a Web browser or compatible client software. Data access services include OPeNDAP, HTTPServer, OGC WCS and WMS, and NetCDFSubset. Metadata level extraction is available through ISO and UDDC. In addition, a web-based browser called Godiva2 is available that allows a user to interactively preview data. THREDDS instances are available that point to the Daymet 2 degree x 2 degree tile data, the Daymet mosaic data set, or prederived climatolgies. In the mosaic data set, each Daymet variable by year is a continuous grid over the entire North American study region as available for each year of data. A user's choice of Daymet THREDDS server will most likely depend on the extent of their current study area.
Automate Downloading of netCDF Files from THREDDS Server
Download a document describing how to automate the download of Daymet 2 degree Tile netCDF files from the THREDDS Daymet Tile server for a known range of years and Tile ID.
Download a document describing how to automate the download of Daymet Mosaic netCDF version 4 files from the THREDDS Daymet Mosaic server for a known range of years.
Watch the segment of a NASA Earthdata Webinar explaining Accessing Daymet Data through a THREDDS Data Server.
Direct Data Access from the ORNL DAAC
Direct download of Daymet data sets with companion documentation files are available from the ORNL DAAC. This includes Mosaic Daily Surface Weather Data, pre-derived Climatologic Summaries, and spatially referenced cross-validation files. You will need to register and sign in through NASA's Earthdata login to download data. Sign in information is provided.