Arnett climate

Arnett Frost Dates and Growing Season

NOAA 1991-2020 normals for Arnett 3NE, 6 km from Arnett, elevation 2429 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Arnett 3NE. 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 15 and the first fall freeze around October 27, a growing season of about 194 days.

Median at 36°F
last April 25, first October 18
Median at 32°F
last April 15, first October 27
Median at 28°F
last April 5, first November 4

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 8May 3May 1Apr 28Apr 25Apr 22Apr 19Apr 15Apr 10
32°FApr 29Apr 25Apr 21Apr 17Apr 15Apr 11Apr 8Apr 5Apr 1
28°FApr 20Apr 15Apr 11Apr 7Apr 5Apr 2Mar 30Mar 23Mar 15
24°FApr 10Apr 5Apr 1Mar 28Mar 23Mar 18Mar 13Mar 7Mar 2
20°FMar 31Mar 23Mar 17Mar 13Mar 9Mar 5Mar 2Feb 27Feb 20
16°FMar 19Mar 11Mar 6Mar 3Feb 28Feb 24Feb 20Feb 14Feb 4

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 3Oct 8Oct 12Oct 15Oct 18Oct 20Oct 23Oct 26Oct 29
32°FOct 14Oct 18Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 8
28°FOct 20Oct 26Oct 30Nov 1Nov 4Nov 7Nov 10Nov 13Nov 18
24°FOct 29Nov 2Nov 6Nov 10Nov 12Nov 16Nov 19Nov 24Nov 30
20°FNov 5Nov 11Nov 15Nov 19Nov 22Nov 26Nov 30Dec 4Dec 10
16°FNov 14Nov 20Nov 25Nov 28Dec 2Dec 6Dec 11Dec 16Dec 24

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°F192186182177174170166161155
32°F214206201197194190186180173
28°F236227222217213209204199192
24°F258250245240235229224218209
20°F283274268262257252247239230
16°F312300292286279274268261250

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
4,456
Cooling degree days, base 65°F
1,477
Growing degree days, base 40°F
6,833
Growing degree days, base 45°F
5,465
Growing degree days, base 50°F
4,249
Growing degree days, base 55°F
3,180
Growing degree days, base 60°F
2,253

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January94704
February757014
March563391
April31416205
May10195462
June9289730
July1438902
August3412874
September43193602
October24330286
November580273
December89608

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 km from Arnett. 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 USC00340332 (Arnett 3NE). Public domain.