Hammon climate

Hammon Frost Dates and Growing Season

NOAA 1991-2020 normals for Hammon 3 Ssw, 5.5 km from Hammon, elevation 1820 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hammon 3 Ssw. 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 16 and the first fall freeze around October 23, a growing season of about 191 days.

Median at 36°F
last April 25, first October 14
Median at 32°F
last April 16, first October 23
Median at 28°F
last April 4, first October 31

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 9May 5May 1Apr 29Apr 25Apr 22Apr 19Apr 16Apr 10
32°FMay 2Apr 27Apr 23Apr 19Apr 16Apr 13Apr 9Apr 5Mar 31
28°FApr 22Apr 16Apr 11Apr 7Apr 4Apr 1Mar 29Mar 23Mar 15
24°FApr 8Apr 3Mar 31Mar 27Mar 22Mar 18Mar 13Mar 9Mar 3
20°FMar 30Mar 22Mar 17Mar 12Mar 9Mar 5Mar 2Feb 26Feb 20
16°FMar 15Mar 10Mar 5Mar 2Feb 27Feb 23Feb 18Feb 13Feb 2

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°FSep 30Oct 4Oct 7Oct 11Oct 14Oct 17Oct 19Oct 22Oct 27
32°FOct 6Oct 14Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 4
28°FOct 16Oct 22Oct 26Oct 29Oct 31Nov 2Nov 5Nov 9Nov 13
24°FOct 23Oct 30Nov 1Nov 4Nov 8Nov 11Nov 14Nov 18Nov 24
20°FOct 31Nov 5Nov 10Nov 14Nov 18Nov 21Nov 25Nov 30Dec 4
16°FNov 7Nov 15Nov 20Nov 24Nov 28Dec 1Dec 6Dec 10Dec 17

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°F190183178175171167162157150
32°F212204198194191186181176168
28°F235225220216211206201196187
24°F255248242237232226222216207
20°F279271264259253248244236228
16°F307296289282277273266259249

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
4,086
Cooling degree days, base 65°F
1,777
Growing degree days, base 40°F
7,354
Growing degree days, base 45°F
5,944
Growing degree days, base 50°F
4,685
Growing degree days, base 55°F
3,572
Growing degree days, base 60°F
2,607

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January89106
February697019
March5076109
April24929260
May73137530
June3355802
July0507972
August1470934
September35227643
October21542317
November552483
December863010

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 5.5 km from Hammon. 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 USC00343871 (Hammon 3 Ssw). Public domain.