Barbour County climate

Barbour County Frost Dates and Growing Season

NOAA 1991-2020 normals for Clayton, 5.4 km from Barbour County, elevation 569 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clayton. 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 11 and the first fall freeze around November 19, a growing season of about 254 days.

Median at 36°F
last March 27, first November 8
Median at 32°F
last March 11, first November 19
Median at 28°F
last February 28, first December 3

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 6Apr 3Mar 31Mar 27Mar 23Mar 18Mar 13Mar 5
32°FMar 30Mar 24Mar 20Mar 16Mar 11Mar 6Mar 2Feb 25Feb 17
28°FMar 20Mar 14Mar 8Mar 3Feb 28Feb 22Feb 16Feb 8Jan 31
24°FMar 9Mar 1Feb 24Feb 16Feb 9Feb 3Jan 30Jan 22Jan 6
20°FFeb 26Feb 13Feb 6Feb 1Jan 28Jan 20Jan 13Jan 6Dec 28
16°FFeb 8Feb 1Jan 30Jan 24Jan 19Jan 16Jan 12Jan 6Jan 1

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 24Oct 29Nov 1Nov 5Nov 8Nov 11Nov 14Nov 19Nov 28
32°FNov 1Nov 7Nov 11Nov 15Nov 19Nov 24Nov 28Dec 3Dec 11
28°FNov 11Nov 19Nov 24Nov 30Dec 3Dec 9Dec 19Dec 29Jan 6
24°FNov 23Dec 3Dec 10Dec 21Dec 28Jan 2Jan 8Jan 16Jan 30
20°FDec 9Dec 20Dec 29Jan 3Jan 8Jan 14Jan 20Jan 27Feb 7
16°FDec 30Jan 1Jan 7Jan 12Jan 15Jan 19Jan 25Jan 30Feb 5

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°F256246238232226222217210201
32°F287274267260254248242237226
28°F321308299291284277269261250
24°F355339331323315306299289277
20°F365365365355346337331321308
16°F365365365365365365365351334

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
94% of years
20°F or colder
67% of years
16°F or colder
27% 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
2,117
Cooling degree days, base 65°F
2,264
Growing degree days, base 40°F
9,343
Growing degree days, base 45°F
7,640
Growing degree days, base 50°F
6,060
Growing degree days, base 55°F
4,628
Growing degree days, base 60°F
3,360

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January541389
February3907123
March25232276
April9680436
May15246696
June0414864
July0507972
August0488953
September4336783
October72123519
November27923232
December4695117

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 5.4 km from Barbour County. 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 USC00011725 (Clayton). Public domain.