Monroeville climate

Monroeville Frost Dates and Growing Season

NOAA 1991-2020 normals for Decatur 1 N, 15 km from Monroeville, elevation 785 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Decatur 1 N. 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 23 and the first fall freeze around October 19, a growing season of about 178 days.

Median at 36°F
last May 4, first October 7
Median at 32°F
last April 23, first October 19
Median at 28°F
last April 11, first October 31

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 19May 14May 10May 6May 4May 1Apr 28Apr 24Apr 19
32°FMay 8May 3Apr 30Apr 26Apr 23Apr 20Apr 17Apr 14Apr 7
28°FApr 28Apr 22Apr 18Apr 14Apr 11Apr 7Apr 4Apr 1Mar 27
24°FApr 16Apr 9Apr 5Apr 3Mar 31Mar 28Mar 24Mar 20Mar 16
20°FApr 5Mar 31Mar 28Mar 24Mar 21Mar 18Mar 15Mar 11Mar 6
16°FMar 28Mar 21Mar 17Mar 14Mar 11Mar 8Mar 4Feb 28Feb 22

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 24Sep 28Oct 1Oct 4Oct 7Oct 9Oct 12Oct 15Oct 20
32°FOct 5Oct 9Oct 13Oct 16Oct 19Oct 22Oct 24Oct 27Nov 1
28°FOct 17Oct 22Oct 25Oct 28Oct 31Nov 2Nov 5Nov 9Nov 15
24°FOct 28Nov 1Nov 4Nov 7Nov 10Nov 14Nov 18Nov 23Nov 30
20°FNov 8Nov 13Nov 17Nov 21Nov 25Nov 29Dec 2Dec 7Dec 17
16°FNov 17Nov 23Nov 28Dec 1Dec 5Dec 9Dec 14Dec 20Dec 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°F176169164160155151147142135
32°F199191186182178173169164156
28°F223216211206201197193187180
24°F250241235230226222217213204
20°F274266258252248244239233224
16°F296287281275270266259253243

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
6,010
Cooling degree days, base 65°F
818
Growing degree days, base 40°F
5,344
Growing degree days, base 45°F
4,170
Growing degree days, base 50°F
3,135
Growing degree days, base 55°F
2,229
Growing degree days, base 60°F
1,456

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21802
February1,03003
March839230
April4626113
May18056351
June21185614
July5260721
August10205660
September9889443
October38413166
November713129
December1,04904

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 15 km from Monroeville. 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 USC00122096 (Decatur 1 N). Public domain.