Dover climate

Dover Frost Dates and Growing Season

NOAA 1991-2020 normals for Dardanelle, 19.3 km from Dover, elevation 370 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dardanelle. 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 1 and the first fall freeze around November 2, a growing season of about 215 days.

Median at 36°F
last April 13, first October 24
Median at 32°F
last April 1, first November 2
Median at 28°F
last March 19, first November 12

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

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

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°F214207202198195191187182175
32°F236228223219215212207202196
28°F262254250244240235230224216
24°F290281274269264259253248240
20°F327315306300295289281273264
16°F360348339333327320314305296

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
3,189
Cooling degree days, base 65°F
2,041
Growing degree days, base 40°F
8,238
Growing degree days, base 45°F
6,698
Growing degree days, base 50°F
5,312
Growing degree days, base 55°F
4,073
Growing degree days, base 60°F
2,982

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January772021
February576146
March38910162
April15149357
May29188625
June0395844
July0530995
August0502967
September9284724
October13376414
November4327122
December696133

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 19.3 km from Dover. 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 USC00031838 (Dardanelle). Public domain.