Jasper County climate

Jasper County Frost Dates and Growing Season

NOAA 1991-2020 normals for Town Bluff Dam, 16 km from Jasper County, elevation 214 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Town Bluff Dam. 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 9 and the first fall freeze around November 22, a growing season of about 258 days.

Median at 36°F
last March 25, first November 8
Median at 32°F
last March 9, first November 22
Median at 28°F
last February 19, first December 7

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

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 25Oct 31Nov 2Nov 5Nov 8Nov 12Nov 16Nov 21Nov 29
32°FNov 1Nov 7Nov 12Nov 17Nov 22Nov 26Dec 1Dec 4Dec 11
28°FNov 15Nov 23Nov 29Dec 3Dec 7Dec 12Dec 21Dec 30Jan 6
24°FDec 3Dec 10Dec 18Dec 25Jan 1Jan 5Jan 10Jan 16Feb 2
20°FDec 15Dec 24Jan 1Jan 4Jan 8Jan 13Jan 19Jan 29Feb 6
16°FDec 20Dec 29Jan 1Jan 5Jan 8Jan 10Jan 19Jan 27Feb 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°F258248241234230224217211202
32°F288279272265258252246238229
28°F329316306298290283275266256
24°F365358345336329322313304292
20°F365365365365365363351338325
16°F365365365365365365365365362

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
84% of years
20°F or colder
42% of years
16°F or colder
11% 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
1,916
Cooling degree days, base 65°F
2,410
Growing degree days, base 40°F
9,668
Growing degree days, base 45°F
7,949
Growing degree days, base 50°F
6,341
Growing degree days, base 55°F
4,870
Growing degree days, base 60°F
3,554

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January5116102
February35112150
March20738317
April7996469
May9265721
June0425874
July0507972
August0513978
September2363811
October66140541
November24233275
December44811132

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 16 km from Jasper 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 USC00419101 (Town Bluff Dam). Public domain.