Keytesville climate

Keytesville Frost Dates and Growing Season

NOAA 1991-2020 normals for Salisbury, 11 km from Keytesville, elevation 730 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Salisbury. 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 12 and the first fall freeze around October 22, a growing season of about 190 days.

Median at 36°F
last April 25, first October 12
Median at 32°F
last April 12, first October 22
Median at 28°F
last April 2, first November 1

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°FMay 9May 4May 1Apr 28Apr 25Apr 22Apr 19Apr 15Apr 10
32°FApr 29Apr 23Apr 19Apr 15Apr 12Apr 9Apr 7Apr 2Mar 30
28°FApr 18Apr 12Apr 8Apr 5Apr 2Mar 31Mar 28Mar 22Mar 17
24°FApr 8Apr 3Mar 30Mar 28Mar 23Mar 19Mar 15Mar 11Mar 6
20°FMar 31Mar 26Mar 20Mar 16Mar 12Mar 9Mar 6Mar 2Feb 23
16°FMar 22Mar 15Mar 11Mar 8Mar 5Mar 2Feb 27Feb 21Feb 13

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°FSep 27Oct 1Oct 5Oct 9Oct 12Oct 14Oct 17Oct 20Oct 25
32°FOct 9Oct 13Oct 16Oct 19Oct 22Oct 24Oct 27Oct 30Nov 2
28°FOct 19Oct 24Oct 27Oct 30Nov 1Nov 2Nov 5Nov 9Nov 14
24°FOct 30Nov 1Nov 4Nov 7Nov 11Nov 13Nov 17Nov 22Nov 28
20°FNov 5Nov 10Nov 14Nov 17Nov 22Nov 26Nov 30Dec 3Dec 9
16°FNov 13Nov 19Nov 24Nov 28Dec 1Dec 4Dec 7Dec 13Dec 20

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°F187181176172168164160155148
32°F211204199194190186181176168
28°F233225220216212208203198191
24°F256249242237232227222218211
20°F279269262257253248244237229
16°F296287281276270267261255246

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
100% 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
5,257
Cooling degree days, base 65°F
1,296
Growing degree days, base 40°F
6,300
Growing degree days, base 45°F
5,039
Growing degree days, base 50°F
3,910
Growing degree days, base 55°F
2,911
Growing degree days, base 60°F
2,038

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,15603
February91309
March685360
April35318189
May11797449
June10272712
July1387851
August2335798
September64153540
October30829237
November650254
December99807

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 11 km from Keytesville. 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 USC00237514 (Salisbury). Public domain.