Looking ahead - The first frost and freeze dates for Kansas

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Meteorological fall began on September 1. It was warm early in the month, with highs over 100 degrees in many locations during Labor Day weekend. It has since turned more seasonable, with pleasant daytime temperatures, cool mornings, and, so far, no threat of cold air. Nowhere in Kansas has there been any frost yet, but it was 39°F in Tribune and 40°F in Colby on the morning of the 12th, a harbinger of colder weather yet to come. The autumnal equinox, which marks the beginning of astronomical fall, is this weekend, specifically on Saturday, September 23, at 1:50 AM central time. We will eventually experience a first frost and, in time, a first freeze, which can end the growing season, depending on how far below freezing the temperature gets and how many hours sub-freezing conditions persist. Exactly when do the first frost and freeze typically occur in Kansas?  In this report, we look at the average dates for those two significant cold weather events.

Data for 20 sites in Kansas were examined using the full period of record at each location. For this study, the first frost date is defined as the first occurrence of a temperature at or below 36°, and the first freeze is defined as the first occurrence of 32°F 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 frost occurred on or before were identified (Table 1). This methodology was repeated for the first freeze data (Table 2).
 

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

First Frost

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

 

 

Looking at the first frost date, the median date is in October, except for the far west and northwest areas of Kansas, where it occurs in late 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 2. Probabilities of the first fall freeze occurring before the given dates.

First Freeze

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

 

There is a 60% or greater chance that the first freeze will occur by the end of October at all locations (Table 2), but the probabilities are higher for earlier dates in the west and north. As with the first frost date, Oberlin has the earliest median date (October 3), and Wichita has the latest date (October 28). September freezes happen occasionally, and occasionally, it’s November before the first freeze, but October is typically the month when the growing season ends. October is also when the normal lows each day decrease the fastest (Table 3); the daily normals drop by 11 to 14 degrees. By month’s end, Goodland, Oberlin, and Tribune all have normal lows below freezing. Only eastern and southern locations have normal lows in the 40s by October 31; all other locations have normal lows in the 30s.

Last year, the first freeze was in mid-October across the entire state, thanks to a cold air mass that invaded the state and brought widespread lows in the 20s, with a few upper teens. The first freeze in 2022 was on the 16th in Goodland, the 17th in Garden City and Hutchinson, and the 18th in Wichita and Parsons. For the northwest, this freeze was later than normal, but in the southeast, it was earlier than normal. What about this year?  It’s too soon to know, but the outlooks for the next two weeks favor above-normal temperatures, so it doesn’t appear that an early freeze will occur in September. As for October, we’ll have to wait and see. Until then, enjoy the pleasant fall weather!


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

Normal Lows

Sep 21

Sep 26

Oct 1

Oct 6

Oct 11

Oct 16

Oct 21

Oct 26

Oct 31

Chanute

57

55

53

51

49

47

45

43

42

Concordia

55

52

50

48

46

44

42

39

37

Dodge City

54

52

50

48

45

43

41

38

36

Emporia

55

53

51

49

47

45

43

41

39

Fort Scott

57

55

53

51

49

47

45

43

42

Garden City

52

50

48

45

43

40

38

36

34

Goodland

48

46

44

41

39

37

35

33

31

Hill City

52

50

47

45

42

40

38

35

33

Horton

54

51

49

47

44

42

40

38

36

Manhattan

55

53

51

49

46

44

42

40

38

Marysville

52

50

48

46

43

41

39

37

35

Oberlin

49

47

44

42

40

37

35

33

31

Olathe

57

55

52

51

49

47

45

43

41

Pratt

55

53

50

48

46

43

41

39

37

Russell

55

52

50

48

45

43

40

38

36

Salina

56

54

52

49

47

45

43

41

38

Sedan

56

54

52

50

48

46

44

42

40

Topeka

55

53

51

49

47

45

43

41

39

Tribune

49

46

44

41

39

36

34

33

31

Wichita

58

56

54

52

49

47

45

43

41

 

 

Matthew Sittel, Assistant State Climatologist
msittel@ksu.edu


Tags:  climate weather first frost first freeze