When do the first freeze and first frost events typically occur in Kansas?

Share Tweet Email

By definition, meteorological fall runs from September 1 through November 30. During this 3-month period, the weather changes dramatically. For example, in Manhattan the average low temperature falls from 62°F to 27°F, and Goodland’s normal lows drop from 56°F to 21°F. Somewhere in between the start and end of meteorological fall we expect both a first frost and a first freeze, the latter of which puts an end to the growing season. The timing varies from year to year, but when on average do these events occur in Kansas?  In this report, we take a look at when we typically experience our first frost and first freeze across the state.

Data for 20 sites in Kansas were examined, using the full period of record at each location. For the purposes of this study, the first frost date is defined as the first occurrence of a temperature at or below 36°, and first freeze is defined as the first occurrence of 32° or colder. The dates that the first frost occurred each year were sorted from earliest to latest, and then the dates on which 10%, 20%, 30%, etc., of the first frosts occurred on or before were identified. This methodology was repeated for the first freeze data. In the absence of short-term forecasts, the percentages can be considered probabilities of event occurrence on or before each given date for each location.

First Frost Probabilities

Looking at the first frost data (Table 1), the median date is in October, except for the far west and northwest areas of Kansas where it is in September. The median date is when there is a 50% chance of the first frost having already occurred. The earliest median date is in Oberlin (September 26), and the latest is in Wichita (October 18). Except for Wichita, there is a 10% probability of the first frost occurring before the first of October at all locations, and a 90% probability that the first frost has occurred by the end of October.

 

Table 1. Probabilities of first fall frost occurring before the given dates.

Probability of First Frost (36°F)

 

10%

20%

30%

40%

50%

60%

70%

80%

90%

Chanute

29-Sep

3-Oct

6-Oct

9-Oct

12-Oct

15-Oct

20-Oct

25-Oct

29-Oct

Concordia

21-Sep

28-Sep

1-Oct

5-Oct

8-Oct

11-Oct

13-Oct

18-Oct

24-Oct

Dodge City

25-Sep

29-Sep

5-Oct

8-Oct

10-Oct

11-Oct

15-Oct

19-Oct

23-Oct

Emporia

28-Sep

1-Oct

6-Oct

8-Oct

10-Oct

13-Oct

16-Oct

19-Oct

25-Oct

Fort Scott

27-Sep

1-Oct

6-Oct

9-Oct

12-Oct

17-Oct

20-Oct

25-Oct

30-Oct

Garden City

20-Sep

25-Sep

27-Sep

30-Sep

5-Oct

8-Oct

10-Oct

13-Oct

18-Oct

Goodland

13-Sep

17-Sep

21-Sep

26-Sep

28-Sep

30-Sep

4-Oct

6-Oct

9-Oct

Hill City

16-Sep

20-Sep

23-Sep

27-Sep

29-Sep

5-Oct

7-Oct

10-Oct

15-Oct

Horton

21-Sep

25-Sep

28-Sep

30-Sep

6-Oct

8-Oct

10-Oct

16-Oct

20-Oct

Manhattan

21-Sep

25-Sep

29-Sep

1-Oct

5-Oct

8-Oct

10-Oct

12-Oct

17-Oct

Marysville

18-Sep

22-Sep

27-Sep

29-Sep

2-Oct

4-Oct

7-Oct

10-Oct

14-Oct

Oberlin

15-Sep

19-Sep

20-Sep

22-Sep

26-Sep

27-Sep

30-Sep

5-Oct

9-Oct

Olathe

26-Sep

1-Oct

5-Oct

8-Oct

10-Oct

13-Oct

17-Oct

20-Oct

26-Oct

Pratt

21-Sep

28-Sep

4-Oct

7-Oct

10-Oct

13-Oct

19-Oct

23-Oct

26-Oct

Russell

22-Sep

26-Sep

1-Oct

3-Oct

6-Oct

10-Oct

11-Oct

15-Oct

21-Oct

Salina

24-Sep

30-Sep

4-Oct

6-Oct

10-Oct

12-Oct

15-Oct

19-Oct

25-Oct

Sedan

27-Sep

30-Sep

5-Oct

8-Oct

12-Oct

16-Oct

19-Oct

23-Oct

26-Oct

Topeka

24-Sep

29-Sep

4-Oct

7-Oct

9-Oct

12-Oct

16-Oct

22-Oct

26-Oct

Tribune

14-Sep

17-Sep

21-Sep

24-Sep

27-Sep

30-Sep

3-Oct

7-Oct

13-Oct

Wichita

1-Oct

7-Oct

10-Oct

13-Oct

18-Oct

22-Oct

24-Oct

27-Oct

3-Nov

 

10%

20%

30%

40%

50%

60%

70%

80%

90%

 

First Freeze Probabilities

There is a 60% or greater chance that the first freeze occurs by the end of October at all locations (Table 2), but the probabilities are higher for earlier dates in the west and north. As was the case with the first frost data, Oberlin has the earliest median date (October 3) and Wichita has the latest date (October 28). September freezes do happen on occasion, and occasionally it’s November before the first freeze happens (as was the case for many locations in Fall of 2021). However, October is on average the month when the growing season ends (Figure 1). You can track the current length of the growing season and when the first freeze occurs real-time at http://mesonet.k-state.edu/airtemp/min/hoursbelow/#mtIndex=7&tab=table-tab. You can also determine how long your area was below certain temperatures thresholds of interest to agriculture in the fall and through the winter.

 

Table 2. Probabilities of first freeze occurring before the given dates.

Probability of First Freeze (32°F)

 

10%

20%

30%

40%

50%

60%

70%

80%

90%

Chanute

10-Oct

16-Oct

19-Oct

22-Oct

25-Oct

27-Oct

29-Oct

3-Nov

6-Nov

Concordia

6-Oct

10-Oct

12-Oct

16-Oct

19-Oct

22-Oct

25-Oct

27-Oct

30-Oct

Dodge City

6-Oct

11-Oct

15-Oct

19-Oct

21-Oct

23-Oct

25-Oct

28-Oct

2-Nov

Emporia

7-Oct

10-Oct

15-Oct

18-Oct

22-Oct

25-Oct

28-Oct

31-Oct

5-Nov

Fort Scott

9-Oct

16-Oct

19-Oct

22-Oct

24-Oct

27-Oct

28-Oct

2-Nov

6-Nov

Garden City

28-Sep

4-Oct

8-Oct

10-Oct

14-Oct

17-Oct

19-Oct

23-Oct

27-Oct

Goodland

22-Sep

26-Sep

30-Sep

4-Oct

8-Oct

11-Oct

13-Oct

18-Oct

22-Oct

Hill City

26-Sep

1-Oct

5-Oct

9-Oct

11-Oct

13-Oct

16-Oct

21-Oct

24-Oct

Horton

29-Sep

5-Oct

7-Oct

10-Oct

12-Oct

17-Oct

22-Oct

25-Oct

29-Oct

Manhattan

1-Oct

7-Oct

10-Oct

12-Oct

15-Oct

19-Oct

21-Oct

25-Oct

29-Oct

Marysville

23-Sep

1-Oct

5-Oct

7-Oct

9-Oct

12-Oct

15-Oct

18-Oct

23-Oct

Oberlin

20-Sep

24-Sep

27-Sep

29-Sep

3-Oct

6-Oct

9-Oct

12-Oct

16-Oct

Olathe

8-Oct

12-Oct

17-Oct

22-Oct

25-Oct

27-Oct

31-Oct

4-Nov

7-Nov

Pratt

6-Oct

10-Oct

14-Oct

19-Oct

22-Oct

24-Oct

27-Oct

31-Oct

5-Nov

Russell

3-Oct

6-Oct

10-Oct

13-Oct

17-Oct

19-Oct

23-Oct

25-Oct

29-Oct

Salina

6-Oct

10-Oct

14-Oct

18-Oct

22-Oct

25-Oct

26-Oct

31-Oct

5-Nov

Sedan

6-Oct

12-Oct

18-Oct

20-Oct

24-Oct

27-Oct

29-Oct

4-Nov

8-Nov

Topeka

4-Oct

8-Oct

12-Oct

17-Oct

20-Oct

24-Oct

27-Oct

29-Oct

3-Nov

Tribune

21-Sep

25-Sep

28-Sep

4-Oct

7-Oct

10-Oct

11-Oct

14-Oct

20-Oct

Wichita

10-Oct

19-Oct

23-Oct

26-Oct

28-Oct

31-Oct

3-Nov

6-Nov

10-Nov

 

https://climate.k-state.edu/maps/special/freeze/Average+Fall+Freeze.png

Figure 1. Average first Fall freeze in Kansas (Kansas Weather Data Library).

 

October is also the month when the normal lows each day decrease the fastest (Table 3); the daily normal temperatures drop by 11 to 14 degrees. By month’s end, Goodland, Oberlin and Tribune all have normal lows below freezing. Only locations in eastern and southern Kansas have normal lows in the 40s by October 31; all other locations have normal lows in the 30s.

 

Table 3. Normal low temperatures for selected dates in October across Kansas. Normals are based on the period 1991-2020.

Change in Normal Low Temperatures Through October

 

Oct 1

Oct 6

Oct 11

Oct 16

Oct 21

Oct 26

Oct 31

Chanute

53

51

49

47

45

43

42

Concordia

50

48

46

44

42

39

37

Dodge City

50

48

45

43

41

38

36

Emporia

51

49

47

45

43

41

39

Fort Scott

53

51

49

47

45

43

42

Garden City

48

45

43

40

38

36

34

Goodland

44

41

39

37

35

33

31

Hill City

47

45

42

40

38

35

33

Horton

49

47

44

42

40

38

36

Manhattan

51

49

46

44

42

40

38

Marysville

48

46

43

41

39

37

35

Oberlin

44

42

40

37

35

33

31

Olathe

52

51

49

47

45

43

41

Pratt

50

48

46

43

41

39

37

Russell

50

48

45

43

40

38

36

Salina

52

49

47

45

43

41

38

Sedan

52

50

48

46

44

42

40

Topeka

51

49

47

45

43

41

39

Tribune

44

41

39

36

34

33

31

Wichita

54

52

49

47

45

43

41

 

As October draws near, monthly and 8 to 14-day outlooks will better define the chances for the first frost and freeze this year, but until then, understanding the range of possibilities helps to plan for the inevitable return of shorter days, colder nights, and sub-freezing temperatures. Until then, let’s enjoy the warmer temperatures while they last, because they won’t for much longer.

 

 

Matthew Sittel, Assistant State Climatologist
msittel@ksu.edu

Christopher “Chip” Redmond, Mesonet Manager
christopherredmond@k-state.edu


Tags:  first frost first freeze 

Search
Subscribe