Valley Brook climate

Valley Brook Frost Dates and Growing Season

NOAA 1991-2020 normals for Oklahoma City Will Rogers AP, 10.9 km from Valley Brook, elevation 1285 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oklahoma City Will Rogers 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 April 4 and the first fall freeze around November 2, a growing season of about 213 days.

Median at 36°F
last April 15, first October 26
Median at 32°F
last April 4, first November 2
Median at 28°F
last March 21, first November 11

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 24Apr 21Apr 18Apr 15Apr 12Apr 9Apr 5Mar 31
32°FApr 20Apr 15Apr 10Apr 7Apr 4Mar 31Mar 28Mar 22Mar 16
28°FApr 7Apr 3Mar 30Mar 26Mar 21Mar 17Mar 13Mar 9Mar 3
24°FMar 29Mar 21Mar 16Mar 12Mar 8Mar 4Mar 1Feb 25Feb 20
20°FMar 16Mar 10Mar 6Mar 2Feb 28Feb 23Feb 19Feb 13Feb 4
16°FMar 7Mar 1Feb 25Feb 19Feb 14Feb 8Feb 2Jan 27Jan 16

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 21Oct 23Oct 26Oct 28Oct 31Nov 3Nov 7
32°FOct 21Oct 26Oct 29Nov 1Nov 2Nov 5Nov 8Nov 12Nov 17
28°FOct 29Nov 1Nov 4Nov 8Nov 11Nov 15Nov 18Nov 22Nov 27
24°FNov 4Nov 9Nov 13Nov 17Nov 21Nov 25Nov 28Dec 2Dec 10
20°FNov 13Nov 20Nov 26Nov 29Dec 3Dec 6Dec 12Dec 18Dec 26
16°FNov 24Dec 1Dec 6Dec 12Dec 18Dec 23Dec 28Jan 4Jan 14

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°F213206201196192188184179173
32°F235226222217213209205199191
28°F257250244239234229224217209
24°F279272267261256251246239231
20°F308300292286279273267261250
16°F338328320313306301294285273

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
99% 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
3,615
Cooling degree days, base 65°F
1,867
Growing degree days, base 40°F
7,790
Growing degree days, base 45°F
6,306
Growing degree days, base 50°F
4,971
Growing degree days, base 55°F
3,788
Growing degree days, base 60°F
2,754

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January832014
February637139
March4379146
April20635300
May50151566
June1357805
July0518983
August0485950
September20251681
October17756361
November4784106
December776020

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 10.9 km from Valley Brook. 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 USW00013967 (Oklahoma City Will Rogers AP). Public domain.