Sterling County climate

Sterling County Frost Dates and Growing Season

NOAA 1991-2020 normals for Sterling City, 6.4 km from Sterling County, elevation 2280 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sterling City. 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 March 31 and the first fall freeze around November 6, a growing season of about 219 days.

Median at 36°F
last April 10, first October 29
Median at 32°F
last March 31, first November 6
Median at 28°F
last March 14, first November 15

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°FApr 27Apr 21Apr 16Apr 13Apr 10Apr 8Apr 4Apr 1Mar 26
32°FApr 16Apr 11Apr 7Apr 3Mar 31Mar 27Mar 22Mar 15Mar 8
28°FApr 6Apr 1Mar 26Mar 20Mar 14Mar 10Mar 6Mar 1Feb 25
24°FMar 25Mar 15Mar 9Mar 5Mar 1Feb 26Feb 22Feb 18Feb 10
20°FMar 8Mar 2Feb 25Feb 20Feb 13Feb 8Feb 2Jan 29Jan 17
16°FMar 1Feb 18Feb 10Feb 4Jan 31Jan 25Jan 18Jan 5Dec 23

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 13Oct 19Oct 23Oct 26Oct 29Nov 1Nov 3Nov 6Nov 11
32°FOct 24Oct 29Nov 1Nov 3Nov 6Nov 8Nov 12Nov 15Nov 21
28°FOct 31Nov 6Nov 9Nov 12Nov 15Nov 18Nov 22Nov 27Dec 2
24°FNov 10Nov 14Nov 19Nov 23Nov 26Nov 30Dec 3Dec 6Dec 14
20°FNov 20Nov 25Nov 30Dec 3Dec 7Dec 12Dec 18Dec 26Jan 4
16°FNov 30Dec 6Dec 12Dec 19Dec 27Jan 3Jan 10Jan 19Feb 1

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°F219213207203199195191185178
32°F244235229224219213209204198
28°F269261255249244238233227219
24°F297287280274270264257250241
20°F333321311305299292286276266
16°F365359347338332326319309299

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
99% of years
16°F or colder
85% 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
2,733
Cooling degree days, base 65°F
2,237
Growing degree days, base 40°F
8,809
Growing degree days, base 45°F
7,193
Growing degree days, base 50°F
5,718
Growing degree days, base 55°F
4,394
Growing degree days, base 60°F
3,234

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January660038
February488275
March31615217
April12084425
May22265709
June0440889
July05351,000
August0514979
September12286725
October10788454
November3818160
December628049

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 6.4 km from Sterling 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 USC00418630 (Sterling City). Public domain.