Cole County climate

Cole County Frost Dates and Growing Season

NOAA 1991-2020 normals for Jefferson City Wtp, 12.4 km from Cole County, elevation 650 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Jefferson City Wtp. 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 8 and the first fall freeze around October 31, a growing season of about 205 days.

Median at 36°F
last April 21, first October 21
Median at 32°F
last April 8, first October 31
Median at 28°F
last March 28, first November 8

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 4Apr 30Apr 27Apr 24Apr 21Apr 17Apr 13Apr 9Apr 4
32°FApr 23Apr 18Apr 14Apr 11Apr 8Apr 5Apr 2Mar 29Mar 23
28°FApr 13Apr 7Apr 3Mar 31Mar 28Mar 24Mar 21Mar 16Mar 9
24°FApr 1Mar 28Mar 24Mar 20Mar 17Mar 14Mar 10Mar 6Feb 28
20°FMar 23Mar 18Mar 13Mar 10Mar 6Mar 3Feb 28Feb 24Feb 17
16°FMar 16Mar 10Mar 6Mar 3Feb 28Feb 24Feb 19Feb 14Feb 5

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 7Oct 12Oct 15Oct 18Oct 21Oct 23Oct 25Oct 27Nov 1
32°FOct 17Oct 22Oct 25Oct 28Oct 31Nov 1Nov 3Nov 6Nov 11
28°FOct 28Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 18Nov 25
24°FNov 4Nov 8Nov 11Nov 15Nov 18Nov 22Nov 27Dec 1Dec 6
20°FNov 11Nov 17Nov 22Nov 26Nov 30Dec 2Dec 7Dec 13Dec 19
16°FNov 21Nov 29Dec 2Dec 7Dec 12Dec 16Dec 20Dec 24Dec 30

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°F202195191187183179175169163
32°F225218213209205201197192186
28°F248240235229225221216211204
24°F272263257252246241238232225
20°F293284276271266261256250243
16°F312303297292286281275269260

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
4,847
Cooling degree days, base 65°F
1,394
Growing degree days, base 40°F
6,596
Growing degree days, base 45°F
5,281
Growing degree days, base 50°F
4,107
Growing degree days, base 55°F
3,070
Growing degree days, base 60°F
2,163

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07605
February843014
March636472
April31622212
May105102465
June8281723
July0413877
August1370834
September49169571
October27531260
November604364
December935011

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 12.4 km from Cole County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00234271 (Jefferson City Wtp). Public domain.