Topeka climate

Topeka Frost Dates and Growing Season

NOAA 1991-2020 normals for Lagrange, 16.1 km from Topeka, elevation 900 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lagrange. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around April 26 and the first fall freeze around October 21, a growing season of about 176 days.

Median at 36°F
last May 6, first October 8
Median at 32°F
last April 26, first October 21
Median at 28°F
last April 16, first November 1

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FMay 22May 17May 14May 10May 6May 3Apr 30Apr 27Apr 23
32°FMay 14May 6May 2Apr 29Apr 26Apr 23Apr 21Apr 17Apr 13
28°FApr 30Apr 24Apr 20Apr 18Apr 16Apr 12Apr 9Apr 5Apr 2
24°FApr 18Apr 12Apr 8Apr 5Apr 3Apr 1Mar 30Mar 25Mar 20
20°FApr 6Apr 2Mar 31Mar 28Mar 25Mar 22Mar 19Mar 15Mar 10
16°FMar 30Mar 25Mar 22Mar 18Mar 15Mar 12Mar 8Mar 3Feb 26

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 25Sep 30Oct 2Oct 5Oct 8Oct 11Oct 14Oct 18Oct 23
32°FOct 5Oct 11Oct 15Oct 18Oct 21Oct 23Oct 26Oct 29Nov 2
28°FOct 19Oct 24Oct 27Oct 30Nov 1Nov 2Nov 5Nov 8Nov 13
24°FNov 1Nov 3Nov 6Nov 8Nov 10Nov 13Nov 17Nov 20Nov 27
20°FNov 7Nov 10Nov 15Nov 17Nov 21Nov 24Nov 28Dec 2Dec 8
16°FNov 15Nov 20Nov 25Nov 29Dec 1Dec 5Dec 8Dec 13Dec 21

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F173167162158154150145139132
32°F197190185181176172168163154
28°F218212207203200196192187180
24°F242235230225222217213209203
20°F266257251246241237232227221
16°F286278271266262257252247239

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
6,427
Cooling degree days, base 65°F
731
Growing degree days, base 40°F
5,057
Growing degree days, base 45°F
3,932
Growing degree days, base 50°F
2,935
Growing degree days, base 55°F
2,064
Growing degree days, base 60°F
1,323

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28001
February1,08201
March892124
April503898
May21652320
June45163569
July9233690
August16188637
September10978421
October4079150
November765024
December1,10302

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 16.1 km from Topeka. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00124730 (Lagrange). Public domain.