Henderson County climate

Henderson County Frost Dates and Growing Season

NOAA 1991-2020 normals for Lexington, 0.5 km from Henderson County, elevation 540 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lexington. 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 5 and the first fall freeze around October 30, a growing season of about 208 days.

Median at 36°F
last April 17, first October 22
Median at 32°F
last April 5, first October 30
Median at 28°F
last March 24, first November 8

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 1Apr 27Apr 23Apr 21Apr 17Apr 14Apr 10Apr 7Apr 1
32°FApr 21Apr 15Apr 11Apr 7Apr 5Apr 2Mar 29Mar 23Mar 17
28°FApr 9Apr 4Apr 1Mar 28Mar 24Mar 19Mar 15Mar 11Mar 4
24°FMar 31Mar 23Mar 18Mar 14Mar 10Mar 6Mar 1Feb 26Feb 18
20°FMar 16Mar 9Mar 5Mar 1Feb 26Feb 22Feb 16Feb 8Jan 31
16°FMar 7Mar 1Feb 25Feb 20Feb 13Feb 7Jan 31Jan 27Jan 17

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 9Oct 13Oct 16Oct 19Oct 22Oct 24Oct 26Oct 30Nov 3
32°FOct 18Oct 22Oct 25Oct 28Oct 30Nov 1Nov 4Nov 7Nov 12
28°FOct 26Oct 31Nov 2Nov 5Nov 8Nov 11Nov 15Nov 20Nov 27
24°FNov 3Nov 7Nov 12Nov 15Nov 19Nov 24Nov 29Dec 3Dec 11
20°FNov 12Nov 20Nov 27Dec 1Dec 5Dec 10Dec 17Dec 23Jan 1
16°FNov 29Dec 7Dec 16Dec 23Dec 27Jan 1Jan 5Jan 10Jan 19

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°F208201196191188184180175167
32°F230221216212208204200195188
28°F254246240235230226220214206
24°F283273266260254250244238227
20°F314304296290284277271264254
16°F347334327320312306300292278

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
97% 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
3,694
Cooling degree days, base 65°F
1,604
Growing degree days, base 40°F
7,466
Growing degree days, base 45°F
5,997
Growing degree days, base 50°F
4,667
Growing degree days, base 55°F
3,492
Growing degree days, base 60°F
2,471

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January849022
February646138
March4785120
April21735294
May57139548
June2317765
July0428893
August0408873
September20222652
October19445333
November486399
December744032

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 0.5 km from Henderson 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 USC00405210 (Lexington). Public domain.