Post climate

Post Frost Dates and Growing Season

NOAA 1991-2020 normals for Post, 0.9 km from Post, elevation 2611 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Post. 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 1 and the first fall freeze around November 9, a growing season of about 223 days.

Median at 36°F
last April 10, first October 30
Median at 32°F
last April 1, first November 9
Median at 28°F
last March 17, first November 19

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 26Apr 21Apr 16Apr 13Apr 10Apr 6Apr 3Mar 31Mar 25
32°FApr 19Apr 11Apr 7Apr 4Apr 1Mar 29Mar 23Mar 17Mar 10
28°FApr 5Apr 1Mar 27Mar 21Mar 17Mar 12Mar 7Mar 3Feb 26
24°FMar 23Mar 16Mar 10Mar 6Mar 2Feb 28Feb 23Feb 18Feb 11
20°FMar 10Mar 3Feb 28Feb 23Feb 18Feb 13Feb 8Jan 31Jan 17
16°FFeb 28Feb 21Feb 12Feb 7Jan 31Jan 23Jan 16Jan 7Dec 31

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 17Oct 20Oct 24Oct 27Oct 30Nov 2Nov 5Nov 8Nov 12
32°FOct 25Oct 30Nov 3Nov 6Nov 9Nov 11Nov 14Nov 18Nov 23
28°FNov 2Nov 9Nov 12Nov 16Nov 19Nov 23Nov 26Dec 1Dec 5
24°FNov 13Nov 18Nov 23Nov 26Nov 29Dec 3Dec 7Dec 12Dec 20
20°FNov 23Nov 29Dec 3Dec 8Dec 14Dec 20Dec 27Jan 4Jan 13
16°FDec 2Dec 9Dec 16Dec 22Dec 29Jan 4Jan 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°F225217212207203198193188181
32°F247240233228223218213207198
28°F273264258252246242235229221
24°F302291284278272266260252243
20°F333321313306300293285277268
16°F365356345336329322315306294

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
87% 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
2,998
Cooling degree days, base 65°F
2,164
Growing degree days, base 40°F
8,545
Growing degree days, base 45°F
6,965
Growing degree days, base 50°F
5,526
Growing degree days, base 55°F
4,244
Growing degree days, base 60°F
3,126

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January702031
February534265
March36316195
April15165379
May38229657
June1429877
July05431,007
August0510975
September13276713
October12788439
November4038149
December666039

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 0.9 km from Post. 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 USC00417206 (Post). Public domain.