Freeze climatology and low temperatures on the Mesonet
As warm weather returns and producers begin to see vegetative growth, interest in freezing temperatures also increase. While we still have some lows dropping to the freezing level, the average date for the last freeze is approaching. The southeast area of the state is the first to see the end of freezing temperatures, while the northwest has an average date of last freeze in May. (Figure 1).
Figure 1. Average spring freeze dates (Weather Data Library).
Historically, almost all parts of the state have recorded freezing temperatures as late as May, but sometimes winter can end early. The earliest last freeze on record in Kansas is March 10, 2012 when many stations last dropped below freezing.
Kansas Mesonet Freeze Monitor
The Kansas Mesonet’s Freeze Monitor (http://mesonet.k-state.edu/weather/freeze/) is now available for the 2019 spring frost/freeze season. This tool displays the coldest temperatures observed across Kansas during the previous 24 hours. It answers the frequent question: How cold did it get last night? Data updates every twenty minutes on both the map and the table (Figure 2).
Another tool important for producers and gardeners is the duration below freezing, as some crops and commodities have lower thresholds for damage. This feature allows users to select options to view maps/data of the duration below freezing (32 degrees F) and the number of hours below 24 degrees F. While both are of interest, the lower threshold is of great importance to wheat growers once jointing occurs and the wheat moves into its reproductive phase. When you view the number of hours, the last spring freeze date for each station is shown with comparison to local climatology.
Figure 2. View of the Freeze Monitor webpage: mesonet.ksu.edu/weather/freeze
Users should be aware that the data displayed in the tables below the maps can be sorted. Clicking on the header of a particular column will sort the table by that column. This makes it much easier to see what area was the coldest in the state, as well as latest freeze and earliest climatological freeze data. There are a number of download options, including table and chart data, and images of the maps (Figure 3).
Figure 3. Download options on the Freeze Monitor website.
The Freeze Monitor is updated in the fall, as the growing season comes to an end, to show the fall freeze climatology.
The Freeze Monitor is available at: http://mesonet.k-state.edu/weather/freeze/
Chip Redmond, Weather Data Library/Mesonet
Mary Knapp, Weather Data Library/Mesonet
Dan Regier, Weather Data Library/Mesonet