MACA Data Portal

Welcome to the MACA data portal. This tool helps you to access MACA data that is hosted on NKN. If you download data, check 'best practices' and join the mailing list.

This tool gives you URL links to either raw MACA data, subsets of MACA data or even some summaries of MACA data.

To decide which download format you should choose, consider what type of machine you will be using to download these:

  • Any machine w/ web browser: Choose 'files of URLs'. Here the tool will create a file of URLs which you can copy/paste into a web browser (to download files one-by-one).
  • Windows Machine: Choose 'files of URLs'. There are Windows programs (i.e. Mass Download or others) that can use a file of URLs to perform a multiple-file download.
  • Macs: Choose 'bash script of cURLS'. This file can be executed to perform a multiple-file download.
  • Linux/Unix: Choose 'bash script of wgets'. This file can be executed to perform a multiple-file download.

To get started, make at least one selection from each category to define the MACA data files that you wish to download.
Then click on the 'Download File' button. A text file will be automatically downloaded to your computer. This text file will have URL paths to all MACA data that satisfies your selections.

Files of URLs:Copy and paste one URL from this text file into a web browser to download the data to your computer. If you make multiple selections in certain categories, multiple filenames meeting your criteria will be added to your file. In this case, note that you will have to be careful about only copy/pasting one filename at a time if you choose URL download.

Files of wget statements: These files are bash scripts of wget statements that can be executed on a Linux/Unix machine. Remember to first make these bash scripts executable (i.e. chmod +x You can execute this bash script with ./

Files of curl statements: These files are bash scripts of curl statements that can be executed on a Mac machine. Remember to first make these bash scripts executable and then you can run them with ./

If you download any data, be sure to join the mailing list to be informed on data updates.

The most efficient way to download MACA data depends on your final interests. Please help the load on our servers by picking the right method for your interests.

If you are interested in point data for only a couple of point locations, likely the most efficient way to do this is to use the Design-Your-Own-CSV tool. You can also use the present tool to download this data.

If you are interested in point data for a lot of points, but within a subset of CONUS, likely the most efficient way to do this is download 'rectangular subsets' of CONUS using this tool and then extract the point locations once you have the regional subsets in hand. Note: if you try to download a lot of points using our server, likely you will bog down our servers and possibly crash them.

If you are interested in very large regional subsets or all the data over CONUS, likely the most efficient way to do this is to download the individual 5-10 year netcdf files and then extract a subset from these once. This data portal will provide you with some links to do that via THREDDs. However, you can also get these files directly faster using FTP for MACAv2-METDATA. Utilizing the aggregated files over years (1950-2005 or 2006-2099) will not work well for large regional subsets or for the full data. It will crash our servers and will take forever for you to get the data. If you are having trouble getting the full data files in a timely manner, please email us and will provide some advice.

Browser issues: There are issues with this data portal and different web browsers. These tools were developed with the Chrome browser. There are issues with the Internet Explorer browser. If there are weirdnesses with things not working right(i.e. you select a point location, but do not get an immediate set of boxes to enter the lat/lon of this point), try to update your version of the Chrome browser and try again. If the weirdnesses persists, contact Katherine Hegewisch(

CSV service: Downloading .CSV file formats for point data extractions is now more stable.
  • We have now fixed the problem with a netcdf4 library in extracting data for our CSV service. The new server has solved this problem. You should not get 'proxy errors' anymore.
  • MACAV1metdata does not seem to work with the CSV service.
  • A 500 server erorr however means that there is something wrong with the code. Please email with what you did to get this.
  • If you get an error message 'Service Temporarily Unavailable', email as likely the server is down.

  • Sometimes you will be allowed to make selections that we did not intend for you to make, due to instabilities in your browser interacting with our form or errors on our part. Note the following:
  • For point extractions, you should not be able to get netcdf data formats. Instead, get CSV formats. Netcdf format is only for rectangular subsets.

  • NETCDF4 vs NETCDF3 File Formats and Supporting Libraries

    Note that the macav2-metdata/macav2-livneh data are in netCDF4 file format (while macav1-metdata is in netCDF 3 class file format). This difference may cause you issues.

    The biggest problem is that netCDF4 files require HDF5 libraries to be properly installed on your system. You may need to update your HDF5 libraries if you are having problems.
    • OPeNDAP requests: If there is incredible latency in a simple point extraction using OPeNDAP, you maybe having problems either with HDF or with your DAP configuration. See this page for more information on how to properly install the NETCDF4 library for data extraction. Specifically, you may need to update your python installation to make sure that you have enabled HDF5 and DAP library support.
    • Viewing Data with ncdump: netCDF4 files require HDF5 libraries. You may need to install the latest HDF5 libraries if you having problems with ncdump.

    Files aggregated over all years in a scenario are available if you do not select 'full domain'


    RCP 4.5

    RCP 8.5


    Download Format:

    MACA domain overlays courtesy of Wenglong Feng, UI