Russell County climate

Russell County Frost Dates and Growing Season

NOAA 1991-2020 normals for Lebanon, 6.2 km from Russell County, elevation 1912 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lebanon. 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 25 and the first fall freeze around October 16, a growing season of about 173 days.

Median at 36°F
last May 7, first October 8
Median at 32°F
last April 25, first October 16
Median at 28°F
last April 13, first October 25

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 24May 18May 13May 10May 7May 4Apr 30Apr 27Apr 22
32°FMay 13May 7May 1Apr 29Apr 25Apr 22Apr 19Apr 16Apr 10
28°FApr 29Apr 22Apr 19Apr 16Apr 13Apr 9Apr 5Apr 2Mar 28
24°FApr 14Apr 8Apr 5Apr 2Mar 31Mar 28Mar 25Mar 20Mar 15
20°FApr 2Mar 29Mar 25Mar 21Mar 18Mar 15Mar 11Mar 6Feb 28
16°FMar 25Mar 18Mar 14Mar 9Mar 5Mar 1Feb 25Feb 18Feb 9

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°FSep 25Oct 1Oct 4Oct 6Oct 8Oct 10Oct 12Oct 15Oct 19
32°FOct 5Oct 9Oct 11Oct 13Oct 16Oct 18Oct 20Oct 24Oct 29
28°FOct 12Oct 16Oct 19Oct 22Oct 25Oct 28Oct 31Nov 3Nov 7
24°FOct 20Oct 25Oct 30Nov 1Nov 3Nov 6Nov 10Nov 13Nov 19
20°FNov 1Nov 5Nov 9Nov 12Nov 15Nov 20Nov 24Nov 30Dec 4
16°FNov 10Nov 17Nov 22Nov 27Dec 1Dec 5Dec 9Dec 17Dec 26

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°F172167162157153149145140133
32°F192187182177173168164160153
28°F216209203199195191186180172
24°F241233226222218214210204197
20°F272261254249244238233227220
16°F305294285279272266260253244

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
100% of years
16°F or colder
100% 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
4,838
Cooling degree days, base 65°F
740
Growing degree days, base 40°F
5,766
Growing degree days, base 45°F
4,437
Growing degree days, base 50°F
3,274
Growing degree days, base 55°F
2,272
Growing degree days, base 60°F
1,424

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January964010
February784013
March654152
April3617166
May15244366
June23144572
July3235697
August4204665
September6493480
October33811191
November632145
December859017

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 6.2 km from Russell 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 USC00444777 (Lebanon). Public domain.