Using the Mesonet Degree Day Calculation Webpage: A case study for corn

Share Tweet Email

Degree days have been featured on the Kansas Mesonet page since the beginning. However, the reports were limited to the growing season (April-October) and to corn and sorghum. The new Degree Days page –  – is designed to provide greater flexibility to our users, including options to select the time period and more built-in calculations. Because of the flexibility, it is somewhat more complicated than the old version. Here’s a run-down of the new features.


  • Station selection: Instead of the old “select by region” scheme, stations can now be selected by name from the selection menu. On desktop computers, a map is also displayed and can be used to select stations. From this menu, the option is also available to select multiple stations. On desktop computers, use ctrl-click to highlight the stations wanted.


  •  Calculation selection: We have expanded the list of possible degree days or growing degree units we can calculate. If none of these quite fit your need, you can select ‘Custom’ to enter your own parameters for the equation (more on that later). We are accepting additional equations/considerations to add to this menu.


  • Beginning/Ending dates: Producers can now enter the exact day of interest as the beginning date. The end date defaults to the current date. Dates from previous years can also be selected.


  • Submit Button: Click to request data for the given time period.



If you have different fields with different planting dates, you can adjust the time frame to match the timing of your operations. For example, using the Silver Lake station below is a comparison of an April 15th planting date versus a May 15th planting date:


  • Table: As before, the table displays the actual degree units, the normal degree units, and the departure from normal, but adds some new features:
    • Sorting data: When pulling data for several stations, clicking on the Actual/Normal/Departure headers will sort records according to the header.
    • Missing data: An asterisk (*) beside a station name indicates that the station had an incomplete data set for the requested time period. Hovering the mouse over the station name will display how many records are missing. To examine the data more closely, see ‘CSV’ below.


  • Graph: Day-by-day data can be graphed for each station as well, by clicking the ‘Graph’ button. The graph is fully interactive and can be saved or printed (see menu in upper right corner of graph). Clicking and dragging across the graph allows the user to zoom in on a time period.
  • CSV Data: All data is available for download in Comma Separated Value (CSV) format. The CSV data section gives the option of downloading the Summary Data (shown in the table) or the Full Data Set (including normal and max/min temperatures for each day). Clicking ‘Display’ will show the data in a new browser window. Clicking ‘Download’ will download the CSV file.
  • References: Shows a list of publications from which the equations are drawn.


Applications of the Mesonet Degree Day Calculation webpage

Taking corn as an example, this information can be useful to gauge the likelihood of a killing frost (high probability for frost by mid-October), which would result in a low test weight and high grain moisture content due to the shortening of the grain filling and drying down period. When planting too late (late May or June), utilization of a short corn maturity (CRM) hybrid will help the crop reach maturity at about the same time as a later-maturing hybrid planted early in the season. Thus, changing to a shorter CRM hybrid would reduce the risk of the corn being impacted by an early fall freeze.

Other potential applications include more precise estimation of crop phenology -- flowering and important growth stages -- for application of nutrients or chemicals, or for implementation of more timely management practices.

The tool presents very useful features and is quite user-friendly. Give it a try and use the tool to make informed management decisions in your operations:  

If you have questions about the product, please don’t hesitate to contact us.

Mary Knapp, Weather Data Library


Christopher Redmond, Kansas Mesonet


Dan Regier, Kansas Mesonet

Ignacio Ciampitti, Crop Production and Cropping Systems Specialist