Cold weather is making its appearance with frost advisories issued this last weekend and freeze warnings this week. The average freeze date in northwest Kansas is as early as the last week in September. However, southeast Kansas does not usually see freezing temperatures until the end of October (Figure 1). Average dates for the first occurrence of 24-degree F temperatures are even later (Figure 2).
Figure 1. Average fall freeze dates (Weather Data Library).
Figure 2. Average 24 oF freeze dates (Weather Data Library).
Historically, almost all parts of the state have recorded freezing temperatures as early as September. Earliest first freeze on record in Kansas is September 3, 1974, when many stations dropped below freezing.
The Kansas Mesonet’s Freeze Monitor (http://mesonet.k-state.edu/weather/freeze/) is now available for the 2019 fall 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? It also tracks the first fall freeze date for each station for comparison to local climatology (http://mesonet.k-state.edu/weather/freeze/#tab=chart-tab&mtIndex=1). Data updates every twenty minutes on both the map and the table (Figure 3).
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 http://mesonet.k-state.edu/weather/freeze/#tab=chart-tab&mtIndex=1) and the number of hours below 24 degrees F (http://mesonet.k-state.edu/weather/freeze/#tab=table-tab&mtIndex=2). While both are of interest, the lower threshold is of great importance to wheat growers later into the fall season.
Figure 3. View of the Freeze Monitor webpage for October 11, 2019, with the Hays station selected as an example. Source: mesonet.ksu.edu/weather/freeze
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 earliest freeze and earliest climatological freeze data. There are a number of download options, including table and chart data, and images of the maps (Figure 4).
Figure 4. Download options on the Freeze Monitor website.
The Freeze Monitor is updated in the spring, as a new growing season arrives, to show the spring freeze climatology.
The Freeze Monitor is available at: http://mesonet.k-state.edu/weather/freeze/
Chip Redmond, Weather Data Library/Mesonet
christopherredmond@ksu.edu
Mary Knapp, Weather Data Library/Mesonet
mknapp@ksu.edu
Dan Regier, Weather Data Library/Mesonet
regierdp@ksu.edu
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