Sumter County climate

Sumter County Frost Dates and Growing Season

NOAA 1991-2020 normals for Livingston, 1.4 km from Sumter County, elevation 128 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Livingston. 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 20 and the first fall freeze around November 9, a growing season of about 234 days.

Median at 36°F
last April 4, first November 1
Median at 32°F
last March 20, first November 9
Median at 28°F
last March 4, first November 21

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 22Apr 15Apr 10Apr 6Apr 4Mar 31Mar 27Mar 22Mar 15
32°FApr 8Apr 2Mar 28Mar 24Mar 20Mar 15Mar 11Mar 6Feb 28
28°FMar 24Mar 18Mar 13Mar 8Mar 4Feb 28Feb 25Feb 20Feb 13
24°FMar 12Mar 4Feb 27Feb 23Feb 18Feb 14Feb 7Feb 1Jan 23
20°FMar 1Feb 21Feb 14Feb 8Feb 2Jan 30Jan 23Jan 16Dec 31
16°FFeb 15Feb 6Feb 1Jan 29Jan 23Jan 18Jan 12Jan 3Dec 26

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 18Oct 22Oct 26Oct 29Nov 1Nov 2Nov 5Nov 8Nov 14
32°FOct 26Nov 1Nov 3Nov 5Nov 9Nov 12Nov 16Nov 21Nov 28
28°FNov 4Nov 8Nov 12Nov 17Nov 21Nov 26Nov 30Dec 4Dec 8
24°FNov 15Nov 22Nov 28Dec 1Dec 5Dec 8Dec 14Dec 25Jan 3
20°FNov 30Dec 5Dec 10Dec 19Dec 25Jan 1Jan 5Jan 12Jan 25
16°FDec 10Dec 19Dec 26Jan 1Jan 4Jan 9Jan 15Jan 23Feb 2

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°F234225220215211206202197188
32°F258249244239234229224218209
28°F288278271266260255250244235
24°F324312304296290283277270260
20°F360346335329322315308299287
16°F365365365364353343334327316

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
90% of years
16°F or colder
61% 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
2,478
Cooling degree days, base 65°F
2,158
Growing degree days, base 40°F
8,919
Growing degree days, base 45°F
7,268
Growing degree days, base 50°F
5,757
Growing degree days, base 55°F
4,392
Growing degree days, base 60°F
3,188

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January605264
February443597
March27723249
April11472413
May19219665
June1412861
July0496961
August0496961
September5316760
October103102467
November35614177
December557483

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 1.4 km from Sumter 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 USC00014798 (Livingston). Public domain.