This page allows you to download observed, sometimes quality controlled, and sometimes estimated once daily reports from the NWS COOP network. Please be sure to understand these caveats before using the data:
- In general, the snowfall data is mostly there. Some years are missing data. Estimating snowfall is very difficult and even the reports of snowfall are questionable. The same applies for snow depth.
- If you are looking to download the entire dataset, please check out this directory!
- If you find errors in the dataset, please let us know! There are numerous folks working on the data quality of this important dataset and we are always interested in feedback.
- The dates presented are the day on which the observation was reported. The values represent a 24 hour period prior to that observation. Unfortunately, presenting the time of the observation is not supported yet. To complicate things, some of the data is actually on the local calendar day.
- On this page, you will also find 'stations' called "Average" or "Climate Division". These virtual stations represent an areal average over a given state or standard climate district.
- You will find download options for daily solar radiation data. Of course, this variable is not observed by this network but is included as a convience. These values were derived from various modelling efforts. This data represents a local calendar day. Only the HRRR estimates have data for recent days, it takes a few months for MERRA-2 and NARR estimates to appear. These values are obtained by simple grid point sampling. You can find an evaluation of these estimates here.
If you are looking for actual observations with no estimating and very little quality control done, check out this page.
The quality controlled data for Iowa is currently updated to 01 Mar 2017. While data is available for dates up until yesterday, the values are estimated by the IEM. The quality controlled data is provided to us by the Iowa State Climatology. News items are posted to the homepage when a month's worth of data is sent to us.
Data is also available from the following states: Illinois , Indiana , Iowa , Kansas, Kentucky , Michigan , Minnesota , Missouri , Nebraska , Ohio , North Dakota , South Dakota , Wisconsin. This information is mostly estimated until NCDC provides updated GHCN datafiles, which the IEM then merges into this dataset. The unfortunate side effect is that data changes as new information becomes available.
If you really need calendar day data and other variables like wind speed and relative humidity, check out the IEM Reanalysis effort.