Krebs climate

Krebs Frost Dates and Growing Season

NOAA 1991-2020 normals for Mcalester Rgnl AP, 8 km from Krebs, elevation 770 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mcalester Rgnl AP. 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 March 31 and the first fall freeze around November 3, a growing season of about 216 days.

Median at 36°F
last April 11, first October 26
Median at 32°F
last March 31, first November 3
Median at 28°F
last March 15, first November 13

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 29Apr 23Apr 19Apr 15Apr 11Apr 9Apr 6Apr 1Mar 27
32°FApr 18Apr 11Apr 6Apr 3Mar 31Mar 27Mar 23Mar 17Mar 11
28°FApr 5Mar 29Mar 24Mar 18Mar 15Mar 12Mar 9Mar 5Feb 26
24°FMar 22Mar 14Mar 11Mar 8Mar 4Mar 1Feb 26Feb 21Feb 14
20°FMar 12Mar 6Mar 2Feb 26Feb 22Feb 16Feb 10Feb 2Jan 26
16°FMar 4Feb 24Feb 15Feb 8Feb 3Jan 30Jan 24Jan 15Jan 3

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 12Oct 17Oct 20Oct 23Oct 26Oct 29Oct 31Nov 3Nov 7
32°FOct 20Oct 25Oct 29Nov 1Nov 3Nov 6Nov 8Nov 13Nov 19
28°FOct 28Nov 2Nov 6Nov 10Nov 13Nov 17Nov 22Nov 27Dec 2
24°FNov 6Nov 11Nov 17Nov 22Nov 26Dec 1Dec 3Dec 7Dec 15
20°FNov 18Nov 26Dec 1Dec 5Dec 9Dec 13Dec 20Dec 26Jan 4
16°FNov 30Dec 7Dec 13Dec 18Dec 25Jan 1Jan 6Jan 13Jan 25

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°F216210204200196192186182175
32°F241232226220216211206202193
28°F269260254248242236230224214
24°F294284278271266261255248238
20°F327314305299292287280273263
16°F360345336330322315308301288

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
93% 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
3,079
Cooling degree days, base 65°F
2,133
Growing degree days, base 40°F
8,452
Growing degree days, base 45°F
6,895
Growing degree days, base 50°F
5,478
Growing degree days, base 55°F
4,210
Growing degree days, base 60°F
3,095

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January742133
February551366
March36519194
April15859362
May34186617
June1396846
July05461,011
August0525990
September14295731
October14089424
November39912157
December676247

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 8 km from Krebs. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00093950 (Mcalester Rgnl AP). Public domain.