Cochran County climate

Cochran County Frost Dates and Growing Season

NOAA 1991-2020 normals for Morton, 14.3 km from Cochran County, elevation 3766 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Morton. 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 31, a growing season of about 199 days.

Median at 36°F
last April 21, first October 19
Median at 32°F
last April 11, first October 31
Median at 28°F
last March 31, first November 7

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 27Apr 24Apr 21Apr 19Apr 16Apr 13Apr 8
32°FApr 26Apr 20Apr 17Apr 14Apr 11Apr 8Apr 5Apr 1Mar 28
28°FApr 17Apr 10Apr 6Apr 3Mar 31Mar 27Mar 22Mar 17Mar 11
24°FApr 4Mar 31Mar 25Mar 20Mar 15Mar 11Mar 7Mar 3Feb 26
20°FMar 23Mar 15Mar 10Mar 6Mar 3Feb 28Feb 24Feb 19Feb 12
16°FMar 11Mar 4Feb 28Feb 22Feb 16Feb 10Feb 6Jan 30Jan 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 4Oct 10Oct 14Oct 17Oct 19Oct 22Oct 25Oct 28Nov 1
32°FOct 16Oct 21Oct 24Oct 28Oct 31Nov 1Nov 4Nov 7Nov 11
28°FOct 24Oct 30Nov 2Nov 5Nov 7Nov 10Nov 13Nov 17Nov 21
24°FNov 2Nov 7Nov 11Nov 14Nov 18Nov 20Nov 24Nov 28Dec 3
20°FNov 10Nov 17Nov 22Nov 25Nov 30Dec 3Dec 6Dec 11Dec 17
16°FNov 22Nov 30Dec 4Dec 8Dec 14Dec 18Dec 23Dec 30Jan 8

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°F198191186182178174170167161
32°F220213207203199195190186180
28°F243236230224220216210204196
24°F270261255249244239234228220
20°F299288281274270265259252244
16°F336324315307301294288279268

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
99% 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
3,605
Cooling degree days, base 65°F
1,585
Growing degree days, base 40°F
7,453
Growing degree days, base 45°F
5,949
Growing degree days, base 50°F
4,608
Growing degree days, base 55°F
3,438
Growing degree days, base 60°F
2,433

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January784012
February608032
March4543120
April21823280
May61153559
June2357805
July0436901
August1390854
September29188610
October19535329
November498190
December756017

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 14.3 km from Cochran 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 USC00416074 (Morton). Public domain.