Clarksville climate

Clarksville Frost Dates and Growing Season

NOAA 1991-2020 normals for Clarksville, 0.6 km from Clarksville, elevation 330 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clarksville. 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 31 and the first fall freeze around November 5, a growing season of about 220 days.

Median at 36°F
last April 12, first October 27
Median at 32°F
last March 31, first November 5
Median at 28°F
last March 18, first November 18

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 27Apr 21Apr 18Apr 15Apr 12Apr 9Apr 6Apr 3Mar 29
32°FApr 14Apr 8Apr 5Apr 2Mar 31Mar 28Mar 24Mar 20Mar 15
28°FApr 3Mar 29Mar 25Mar 21Mar 18Mar 15Mar 12Mar 7Mar 1
24°FMar 21Mar 17Mar 12Mar 9Mar 6Mar 3Feb 27Feb 22Feb 13
20°FMar 12Mar 7Mar 2Feb 26Feb 21Feb 15Feb 10Feb 4Jan 25
16°FMar 1Feb 19Feb 13Feb 6Feb 2Jan 28Jan 22Jan 16Jan 7

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 14Oct 19Oct 22Oct 25Oct 27Oct 30Nov 1Nov 4Nov 9
32°FOct 23Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 15Nov 21
28°FNov 2Nov 7Nov 11Nov 14Nov 18Nov 21Nov 26Dec 1Dec 7
24°FNov 15Nov 21Nov 26Nov 30Dec 3Dec 7Dec 12Dec 19Dec 30
20°FDec 1Dec 8Dec 14Dec 21Dec 27Jan 1Jan 5Jan 13Jan 20
16°FDec 17Dec 27Jan 1Jan 6Jan 11Jan 15Jan 19Jan 26Feb 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°F217211205201198194190185179
32°F242233228224220216212207200
28°F269260253249244239233228221
24°F302294287281275269263257248
20°F331323314307303297291284274
16°F365355346338332326318309301

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
85% 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
3,537
Cooling degree days, base 65°F
1,593
Growing degree days, base 40°F
7,478
Growing degree days, base 45°F
5,976
Growing degree days, base 50°F
4,639
Growing degree days, base 55°F
3,464
Growing degree days, base 60°F
2,450

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January797017
February637031
March4866111
April21132288
May58128535
June3309756
July0453917
August0396860
September16223657
October18843331
November4443103
December698033

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 0.6 km from Clarksville. 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 USC00441746 (Clarksville). Public domain.