Glenpool climate

Glenpool Frost Dates and Growing Season

NOAA 1991-2020 normals for Tulsa R L Jones Jr AP, 9.6 km from Glenpool, elevation 638 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tulsa R L Jones Jr 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 30 and the first fall freeze around November 4, a growing season of about 220 days.

Median at 36°F
last April 9, first October 26
Median at 32°F
last March 30, first November 4
Median at 28°F
last March 15, first November 14

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 26Apr 21Apr 17Apr 13Apr 9Apr 7Apr 4Mar 31Mar 26
32°FApr 17Apr 9Apr 5Apr 2Mar 30Mar 27Mar 23Mar 18Mar 10
28°FApr 3Mar 28Mar 23Mar 19Mar 15Mar 12Mar 9Mar 4Feb 27
24°FMar 20Mar 14Mar 10Mar 7Mar 4Feb 28Feb 25Feb 21Feb 12
20°FMar 12Mar 6Mar 1Feb 26Feb 22Feb 16Feb 11Feb 4Jan 27
16°FMar 4Feb 26Feb 19Feb 12Feb 6Feb 1Jan 28Jan 20Jan 8

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 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 3Nov 8
32°FOct 21Oct 26Oct 29Nov 1Nov 4Nov 6Nov 11Nov 15Nov 20
28°FOct 31Nov 3Nov 7Nov 11Nov 14Nov 18Nov 22Nov 27Dec 2
24°FNov 7Nov 13Nov 18Nov 22Nov 26Nov 30Dec 4Dec 7Dec 14
20°FNov 18Nov 25Nov 30Dec 4Dec 8Dec 12Dec 17Dec 23Dec 31
16°FDec 1Dec 8Dec 13Dec 19Dec 24Dec 29Jan 2Jan 9Jan 19

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°F219213208203199196191185177
32°F243235229225220215211204195
28°F266258252247241237232226218
24°F292283277272265261256250241
20°F323311304297291286280274265
16°F354343335327320313305298286

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
96% 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
3,374
Cooling degree days, base 65°F
2,146
Growing degree days, base 40°F
8,250
Growing degree days, base 45°F
6,732
Growing degree days, base 50°F
5,363
Growing degree days, base 55°F
4,147
Growing degree days, base 60°F
3,073

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January809020
February610247
March40716165
April16859353
May37189617
June1416865
July05661,031
August0530995
September14287723
October15676394
November4377124
December737130

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 9.6 km from Glenpool. 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 USW00053908 (Tulsa R L Jones Jr AP). Public domain.