Atchison County climate

Atchison County Frost Dates and Growing Season

NOAA 1991-2020 normals for Atchison, 18 km from Atchison County, elevation 945 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Atchison. 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 11 and the first fall freeze around October 29, a growing season of about 199 days.

Median at 36°F
last April 21, first October 20
Median at 32°F
last April 11, first October 29
Median at 28°F
last April 1, first November 5

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 3Apr 30Apr 26Apr 23Apr 21Apr 18Apr 16Apr 12Apr 7
32°FApr 23Apr 19Apr 16Apr 13Apr 11Apr 8Apr 6Apr 2Mar 29
28°FApr 14Apr 10Apr 6Apr 4Apr 1Mar 30Mar 27Mar 22Mar 15
24°FApr 5Apr 1Mar 30Mar 26Mar 22Mar 19Mar 15Mar 10Mar 5
20°FMar 29Mar 23Mar 19Mar 15Mar 12Mar 8Mar 5Mar 2Feb 24
16°FMar 19Mar 14Mar 9Mar 7Mar 4Mar 1Feb 27Feb 23Feb 15

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°FOct 2Oct 9Oct 13Oct 17Oct 20Oct 22Oct 24Oct 27Oct 31
32°FOct 15Oct 20Oct 23Oct 26Oct 29Oct 31Nov 2Nov 5Nov 10
28°FOct 22Oct 28Nov 1Nov 2Nov 5Nov 8Nov 11Nov 14Nov 21
24°FNov 1Nov 4Nov 8Nov 11Nov 14Nov 17Nov 22Nov 26Dec 1
20°FNov 6Nov 11Nov 16Nov 20Nov 24Nov 27Dec 1Dec 4Dec 10
16°FNov 14Nov 21Nov 26Nov 29Dec 2Dec 6Dec 11Dec 16Dec 22

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°F199194188184180176172166160
32°F219212208204199195191186179
28°F241233227223218214211205197
24°F261253246242237232226221214
20°F280271264260256251246239232
16°F299289283278273268263258250

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
5,266
Cooling degree days, base 65°F
1,360
Growing degree days, base 40°F
6,388
Growing degree days, base 45°F
5,133
Growing degree days, base 50°F
4,006
Growing degree days, base 55°F
2,996
Growing degree days, base 60°F
2,112

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16800
February91807
March678261
April34614186
May10198464
June6289733
July0417882
August2357820
September51156556
October29326247
November672146
December1,03104

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 18 km from Atchison County. 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 USC00140405 (Atchison). Public domain.