Montgomery County climate

Montgomery County Frost Dates and Growing Season

NOAA 1991-2020 normals for Mt Sterling, 3.2 km from Montgomery County, elevation 960 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mt Sterling. 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 24 and the first fall freeze around October 18, a growing season of about 175 days.

Median at 36°F
last May 5, first October 8
Median at 32°F
last April 24, first October 18
Median at 28°F
last April 13, first October 28

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 21May 15May 12May 8May 5May 1Apr 29Apr 25Apr 21
32°FMay 12May 5May 1Apr 28Apr 24Apr 22Apr 19Apr 15Apr 9
28°FApr 29Apr 23Apr 20Apr 16Apr 13Apr 10Apr 6Apr 2Mar 28
24°FApr 18Apr 12Apr 7Apr 4Apr 1Mar 30Mar 26Mar 21Mar 15
20°FApr 6Apr 2Mar 30Mar 25Mar 21Mar 18Mar 14Mar 9Mar 1
16°FMar 26Mar 20Mar 17Mar 13Mar 8Mar 5Mar 1Feb 24Feb 16

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 26Sep 30Oct 3Oct 6Oct 8Oct 11Oct 13Oct 16Oct 20
32°FOct 6Oct 10Oct 13Oct 16Oct 18Oct 20Oct 22Oct 25Oct 29
28°FOct 15Oct 20Oct 23Oct 26Oct 28Oct 31Nov 2Nov 6Nov 10
24°FOct 26Oct 30Nov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 23
20°FNov 2Nov 7Nov 11Nov 14Nov 18Nov 22Nov 26Dec 1Dec 5
16°FNov 11Nov 17Nov 22Nov 26Dec 1Dec 3Dec 7Dec 13Dec 23

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°F174168164160156153148143135
32°F195189184179175171167162155
28°F220213207202198194189185177
24°F243235229225221217212207200
20°F268260252246241236231226219
16°F297287279273268262256250242

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
5,046
Cooling degree days, base 65°F
989
Growing degree days, base 40°F
5,985
Growing degree days, base 45°F
4,695
Growing degree days, base 50°F
3,553
Growing degree days, base 55°F
2,553
Growing degree days, base 60°F
1,698

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03208
February853011
March681258
April36413179
May13576413
June16202636
July2306769
August5258718
September69117499
October32416205
November643146
December924012

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 3.2 km from Montgomery 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 USC00155640 (Mt Sterling). Public domain.