Marvell climate

Marvell Frost Dates and Growing Season

NOAA 1991-2020 normals for Marianna 2 S, 24.4 km from Marvell, elevation 234 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Marianna 2 S. 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 18 and the first fall freeze around November 11, a growing season of about 238 days.

Median at 36°F
last March 31, first November 1
Median at 32°F
last March 18, first November 11
Median at 28°F
last March 7, first November 26

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 18Apr 10Apr 6Apr 3Mar 31Mar 29Mar 25Mar 20Mar 14
32°FApr 5Mar 31Mar 26Mar 22Mar 18Mar 15Mar 12Mar 7Mar 1
28°FMar 22Mar 17Mar 14Mar 10Mar 7Mar 4Mar 1Feb 25Feb 19
24°FMar 14Mar 7Mar 4Feb 28Feb 25Feb 20Feb 14Feb 6Jan 30
20°FMar 5Feb 27Feb 20Feb 14Feb 7Feb 1Jan 28Jan 19Jan 7
16°FFeb 23Feb 8Feb 2Jan 30Jan 25Jan 20Jan 13Jan 6Dec 29

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 19Oct 23Oct 26Oct 29Nov 1Nov 3Nov 6Nov 9Nov 15
32°FOct 28Nov 1Nov 5Nov 8Nov 11Nov 16Nov 20Nov 25Dec 1
28°FNov 6Nov 11Nov 17Nov 21Nov 26Dec 1Dec 4Dec 9Dec 19
24°FNov 19Nov 26Dec 1Dec 5Dec 11Dec 17Dec 23Dec 29Jan 6
20°FDec 2Dec 11Dec 20Dec 26Dec 31Jan 3Jan 9Jan 16Jan 29
16°FDec 14Dec 25Jan 1Jan 4Jan 10Jan 15Jan 19Jan 27Feb 5

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°F237229224219215210206200194
32°F263254248242238233228222214
28°F292282274268263258251245238
24°F323312305299292285278271262
20°F359344335330321314308301289
16°F365365365359350342335326311

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
99% of years
20°F or colder
93% of years
16°F or colder
68% 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
3,115
Cooling degree days, base 65°F
2,081
Growing degree days, base 40°F
8,365
Growing degree days, base 45°F
6,818
Growing degree days, base 50°F
5,410
Growing degree days, base 55°F
4,148
Growing degree days, base 60°F
3,037

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January760130
February574154
March39012172
April14963376
May26222660
June1415864
July0502967
August0474939
September12293730
October13887422
November40210147
December663148

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 24.4 km from Marvell. 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 USC00034638 (Marianna 2 S). Public domain.