Lexington climate

Lexington Frost Dates and Growing Season

NOAA 1991-2020 normals for Lexington, 0.2 km from Lexington, elevation 726 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 March 31 and the first fall freeze around November 6, a growing season of about 221 days.

Median at 36°F
last April 13, first October 28
Median at 32°F
last March 31, first November 6
Median at 28°F
last March 18, first November 17

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 28Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 3Mar 29
32°FApr 13Apr 8Apr 5Apr 2Mar 31Mar 28Mar 24Mar 20Mar 14
28°FApr 3Mar 29Mar 25Mar 21Mar 18Mar 15Mar 11Mar 6Feb 28
24°FMar 24Mar 18Mar 14Mar 9Mar 5Mar 1Feb 23Feb 14Feb 3
20°FMar 13Mar 5Feb 28Feb 19Feb 10Feb 2Jan 28Jan 20Jan 10
16°FMar 4Feb 19Feb 6Jan 31Jan 26Jan 21Jan 15Jan 9Jan 1

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 16Oct 20Oct 23Oct 26Oct 28Oct 30Nov 1Nov 4Nov 9
32°FOct 26Oct 30Nov 1Nov 4Nov 6Nov 8Nov 11Nov 15Nov 21
28°FNov 3Nov 7Nov 11Nov 14Nov 17Nov 21Nov 26Dec 1Dec 6
24°FNov 12Nov 18Nov 25Nov 30Dec 3Dec 8Dec 17Dec 26Jan 2
20°FNov 27Dec 4Dec 11Dec 20Dec 25Dec 31Jan 4Jan 10Jan 18
16°FDec 11Dec 22Dec 30Jan 2Jan 7Jan 11Jan 16Jan 24Feb 6

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°F218210206202198194190185179
32°F243235229225221216212206200
28°F274265258252247242236230222
24°F314301293285279272265257247
20°F348336329322313306298289277
16°F365365360350343335329319306

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
97% of years
16°F or colder
75% 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
2,884
Cooling degree days, base 65°F
1,744
Growing degree days, base 40°F
8,132
Growing degree days, base 45°F
6,522
Growing degree days, base 50°F
5,069
Growing degree days, base 55°F
3,781
Growing degree days, base 60°F
2,676

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January670046
February506159
March3809162
April16939330
May37156584
June1349798
July0462927
August0406871
September7253696
October12763406
November3895131
December599159

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 0.2 km from Lexington. 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 USC00095165 (Lexington). Public domain.