Ardmore climate

Ardmore Frost Dates and Growing Season

NOAA 1991-2020 normals for Ardmore, 0.8 km from Ardmore, elevation 885 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ardmore. 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 223 days.

Median at 36°F
last April 9, first October 27
Median at 32°F
last March 30, first November 4
Median at 28°F
last March 17, first November 18

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 24Apr 19Apr 15Apr 11Apr 9Apr 6Apr 3Mar 31Mar 24
32°FApr 14Apr 8Apr 5Apr 1Mar 30Mar 26Mar 21Mar 17Mar 9
28°FApr 3Mar 30Mar 25Mar 20Mar 17Mar 13Mar 8Mar 3Feb 25
24°FMar 25Mar 18Mar 12Mar 8Mar 4Feb 28Feb 24Feb 17Feb 9
20°FMar 13Mar 5Feb 28Feb 23Feb 17Feb 11Feb 5Jan 31Jan 20
16°FMar 1Feb 21Feb 12Feb 5Jan 31Jan 27Jan 20Jan 12Jan 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 15Oct 20Oct 23Oct 25Oct 27Oct 30Nov 1Nov 4Nov 8
32°FOct 23Oct 28Oct 31Nov 2Nov 4Nov 8Nov 11Nov 16Nov 23
28°FNov 1Nov 6Nov 10Nov 14Nov 18Nov 22Nov 27Dec 1Dec 5
24°FNov 12Nov 19Nov 24Nov 29Dec 1Dec 4Dec 8Dec 15Dec 27
20°FNov 27Dec 2Dec 7Dec 11Dec 17Dec 24Dec 30Jan 4Jan 14
16°FDec 7Dec 14Dec 23Dec 30Jan 1Jan 6Jan 11Jan 19Jan 30

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°F222215211206202197193187180
32°F247238231227223218214207199
28°F275264258252247242237230222
24°F301290283277272265260253245
20°F332319311305299293288279269
16°F363351342334328321313307297

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
87% 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
3,061
Cooling degree days, base 65°F
1,861
Growing degree days, base 40°F
8,171
Growing degree days, base 45°F
6,605
Growing degree days, base 50°F
5,179
Growing degree days, base 55°F
3,907
Growing degree days, base 60°F
2,796

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January747036
February560150
March3799167
April14343356
May32185618
June0366816
July0479944
August0442907
September11266705
October13265404
November4025126
December655150

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 0.8 km from Ardmore. 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 USC00400235 (Ardmore). Public domain.