Ash Flat climate

Ash Flat Frost Dates and Growing Season

NOAA 1991-2020 normals for Hardy, 10.8 km from Ash Flat, elevation 400 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hardy. 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 October 31, a growing season of about 210 days.

Median at 36°F
last April 14, first October 22
Median at 32°F
last April 4, first October 31
Median at 28°F
last March 24, 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 21Apr 18Apr 14Apr 11Apr 8Apr 4Mar 30
32°FApr 21Apr 14Apr 10Apr 7Apr 4Apr 1Mar 29Mar 25Mar 18
28°FApr 10Apr 3Mar 31Mar 28Mar 24Mar 20Mar 16Mar 12Mar 6
24°FMar 31Mar 26Mar 20Mar 16Mar 12Mar 9Mar 5Mar 1Feb 24
20°FMar 19Mar 13Mar 9Mar 5Mar 1Feb 27Feb 24Feb 17Feb 10
16°FMar 11Mar 5Mar 1Feb 25Feb 20Feb 15Feb 9Feb 3Jan 26

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 9Oct 14Oct 17Oct 20Oct 22Oct 24Oct 26Oct 29Nov 1
32°FOct 18Oct 23Oct 26Oct 29Oct 31Nov 2Nov 5Nov 8Nov 14
28°FOct 28Nov 1Nov 3Nov 6Nov 9Nov 11Nov 15Nov 20Nov 25
24°FNov 4Nov 8Nov 12Nov 16Nov 20Nov 24Nov 29Dec 2Dec 10
20°FNov 10Nov 17Nov 23Nov 27Dec 1Dec 5Dec 10Dec 16Dec 24
16°FNov 21Nov 29Dec 4Dec 11Dec 17Dec 23Dec 29Jan 4Jan 13

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°F209203198193189185181175169
32°F230222218213210205200195188
28°F253245240234229225220214208
24°F278270262257251246239234226
20°F304294287281276271263257248
16°F329319311306300293287279267

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
3,945
Cooling degree days, base 65°F
1,560
Growing degree days, base 40°F
7,259
Growing degree days, base 45°F
5,825
Growing degree days, base 50°F
4,537
Growing degree days, base 55°F
3,397
Growing degree days, base 60°F
2,406

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January897013
February699132
March5067109
April22235289
May66124524
June2313760
July0439904
August1405869
September28191614
October21243317
November516386
December795021

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 10.8 km from Ash Flat. 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 USC00033132 (Hardy). Public domain.