Ardmore climate

Ardmore Frost Dates and Growing Season

NOAA 1991-2020 normals for Ardmore, 1.7 km from Ardmore, elevation 841 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 15 and the first fall freeze around November 14, a growing season of about 244 days.

Median at 36°F
last March 27, first November 5
Median at 32°F
last March 15, first November 14
Median at 28°F
last March 3, first November 26

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

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

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°F246238232226221216211205196
32°F269261255250244239233227218
28°F296286279273268263256249241
24°F324315307300293286279273262
20°F350339333326319313306299285
16°F365365359350344338332322312

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
95% of years
16°F or colder
76% 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
2,667
Cooling degree days, base 65°F
2,523
Growing degree days, base 40°F
9,181
Growing degree days, base 45°F
7,564
Growing degree days, base 50°F
6,080
Growing degree days, base 55°F
4,742
Growing degree days, base 60°F
3,556

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January694036
February490381
March30522238
April10280432
May16237687
June1459909
July06171,082
August06041,069
September8365807
October92118497
November34018190
December621153

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 1.7 km from Ardmore. 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 USC00340292 (Ardmore). Public domain.