Jasper County climate

Jasper County Frost Dates and Growing Season

NOAA 1991-2020 normals for Monticello, 2.1 km from Jasper County, elevation 518 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Monticello. 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 4 and the first fall freeze around November 1, a growing season of about 211 days.

Median at 36°F
last April 17, first October 23
Median at 32°F
last April 4, first November 1
Median at 28°F
last March 24, first November 11

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 2Apr 27Apr 24Apr 21Apr 17Apr 14Apr 10Apr 6Mar 31
32°FApr 20Apr 15Apr 11Apr 7Apr 4Apr 1Mar 30Mar 25Mar 18
28°FApr 7Apr 3Mar 30Mar 27Mar 24Mar 20Mar 16Mar 11Mar 1
24°FMar 28Mar 24Mar 19Mar 15Mar 10Mar 5Feb 28Feb 24Feb 14
20°FMar 17Mar 10Mar 4Feb 28Feb 23Feb 16Feb 9Jan 31Jan 22
16°FMar 5Feb 27Feb 17Feb 9Feb 2Jan 29Jan 23Jan 15Jan 2

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 12Oct 16Oct 19Oct 21Oct 23Oct 25Oct 28Oct 31Nov 4
32°FOct 20Oct 24Oct 27Oct 30Nov 1Nov 3Nov 5Nov 10Nov 16
28°FOct 30Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 24Dec 1
24°FNov 7Nov 12Nov 17Nov 21Nov 25Nov 30Dec 3Dec 7Dec 21
20°FNov 20Nov 27Dec 1Dec 5Dec 10Dec 18Dec 26Jan 2Jan 10
16°FDec 4Dec 11Dec 19Dec 27Jan 1Jan 5Jan 11Jan 18Jan 30

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°F211203198194190186182177170
32°F233225220215211207203198191
28°F260251244239234229224219212
24°F296283275268263257250244236
20°F334323312304297290282273261
16°F365355344335329321311304291

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
99% of years
16°F or colder
89% 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
2,838
Cooling degree days, base 65°F
1,779
Growing degree days, base 40°F
8,204
Growing degree days, base 45°F
6,582
Growing degree days, base 50°F
5,118
Growing degree days, base 55°F
3,827
Growing degree days, base 60°F
2,716

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January671039
February514154
March3618171
April15638338
May33162594
June1347796
July0470935
August0432897
September9253694
October12361409
November3786138
December591154

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 2.1 km from Jasper County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00095988 (Monticello). Public domain.