Monroe County climate

Monroe County Frost Dates and Growing Season

NOAA 1991-2020 normals for Whatley, 33.8 km from Monroe County, elevation 170 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Whatley. 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 22 and the first fall freeze around November 8, a growing season of about 231 days.

Median at 36°F
last April 4, first October 30
Median at 32°F
last March 22, first November 8
Median at 28°F
last March 8, first November 21

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 22Apr 16Apr 11Apr 7Apr 4Mar 31Mar 28Mar 24Mar 17
32°FApr 9Apr 4Mar 30Mar 26Mar 22Mar 18Mar 14Mar 10Mar 3
28°FMar 27Mar 21Mar 17Mar 13Mar 8Mar 4Feb 28Feb 24Feb 17
24°FMar 15Mar 8Mar 1Feb 26Feb 23Feb 18Feb 13Feb 4Jan 29
20°FMar 3Feb 23Feb 16Feb 10Feb 4Jan 31Jan 28Jan 22Jan 10
16°FFeb 23Feb 9Feb 2Jan 31Jan 27Jan 22Jan 15Jan 9Dec 31

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 27Oct 30Nov 2Nov 4Nov 8Nov 14
32°FOct 24Oct 29Nov 1Nov 4Nov 8Nov 12Nov 15Nov 20Nov 28
28°FNov 2Nov 7Nov 12Nov 16Nov 21Nov 25Dec 1Dec 5Dec 11
24°FNov 15Nov 24Nov 30Dec 3Dec 8Dec 14Dec 22Dec 30Jan 6
20°FDec 1Dec 8Dec 16Dec 25Jan 1Jan 4Jan 8Jan 14Jan 25
16°FDec 13Dec 25Dec 31Jan 4Jan 7Jan 12Jan 17Jan 25Feb 2

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°F233224219213209205200195188
32°F258248242236231226221214208
28°F289278269263256251245237229
24°F326315306298291283275266257
20°F357342334328320314306299285
16°F365365365355345337332322310

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
94% of years
16°F or colder
70% 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
2,289
Cooling degree days, base 65°F
2,147
Growing degree days, base 40°F
9,066
Growing degree days, base 45°F
7,387
Growing degree days, base 50°F
5,841
Growing degree days, base 55°F
4,441
Growing degree days, base 60°F
3,205

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January582169
February4173104
March26523255
April10480429
May14225676
June0393843
July0476941
August0482947
September3334781
October93106482
November30621214
December5054101

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 33.8 km from Monroe County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00018867 (Whatley). Public domain.