Arma climate

Arma Frost Dates and Growing Season

NOAA 1991-2020 normals for Girard, 12.9 km from Arma, elevation 990 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Girard. 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 4 and the first fall freeze around November 1, a growing season of about 209 days.

Median at 36°F
last April 15, first October 22
Median at 32°F
last April 4, first November 1
Median at 28°F
last March 26, first November 9

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 30Apr 25Apr 22Apr 18Apr 15Apr 12Apr 8Apr 5Mar 31
32°FApr 21Apr 14Apr 10Apr 6Apr 4Apr 1Mar 29Mar 24Mar 19
28°FApr 9Apr 4Apr 1Mar 29Mar 26Mar 21Mar 17Mar 13Mar 7
24°FApr 1Mar 27Mar 20Mar 17Mar 13Mar 9Mar 6Mar 3Feb 26
20°FMar 21Mar 15Mar 10Mar 6Mar 3Feb 28Feb 26Feb 20Feb 12
16°FMar 14Mar 8Mar 3Feb 28Feb 25Feb 20Feb 14Feb 8Feb 1

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 16Oct 20Oct 22Oct 24Oct 27Oct 30Nov 2
32°FOct 17Oct 22Oct 26Oct 29Nov 1Nov 2Nov 5Nov 9Nov 14
28°FOct 27Oct 31Nov 2Nov 5Nov 9Nov 12Nov 16Nov 21Nov 26
24°FNov 1Nov 7Nov 12Nov 15Nov 18Nov 23Nov 27Dec 1Dec 5
20°FNov 10Nov 15Nov 21Nov 26Nov 30Dec 2Dec 6Dec 11Dec 18
16°FNov 20Nov 27Dec 1Dec 5Dec 10Dec 15Dec 20Dec 26Jan 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°F210202197192188183178173166
32°F232224219214209205201195188
28°F254245240234229224219214207
24°F275266260254249244239233223
20°F296286279274269265259251244
16°F319309300295289285277270262

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
4,555
Cooling degree days, base 65°F
1,539
Growing degree days, base 40°F
6,913
Growing degree days, base 45°F
5,563
Growing degree days, base 50°F
4,350
Growing degree days, base 55°F
3,275
Growing degree days, base 60°F
2,337

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02404
February797017
March580486
April28821232
May86112494
June5311756
July0453918
August1415879
September41188598
October24835285
November580272
December905011

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 12.9 km from Arma. 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 USC00143074 (Girard). Public domain.