Petal climate

Petal Frost Dates and Growing Season

NOAA 1991-2020 normals for Hattiesburg Chain Muni AP, 7.3 km from Petal, elevation 151 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hattiesburg Chain Muni AP. 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 8 and the first fall freeze around November 15, a growing season of about 252 days.

Median at 36°F
last March 24, first November 4
Median at 32°F
last March 8, first November 15
Median at 28°F
last February 22, first November 30

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 13Apr 6Apr 2Mar 29Mar 24Mar 20Mar 16Mar 11Mar 3
32°FMar 28Mar 22Mar 16Mar 12Mar 8Mar 3Feb 28Feb 23Feb 16
28°FMar 15Mar 8Mar 2Feb 27Feb 22Feb 16Feb 10Feb 3Jan 26
24°FMar 3Feb 23Feb 14Feb 7Feb 2Jan 29Jan 23Jan 15Jan 2
20°FFeb 17Feb 4Jan 31Jan 27Jan 22Jan 17Jan 10Jan 3Dec 26
16°FFeb 4Jan 30Jan 25Jan 21Jan 17Jan 14Jan 8Jan 2Dec 25

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 23Oct 27Oct 30Nov 1Nov 4Nov 6Nov 10Nov 14Nov 19
32°FNov 1Nov 5Nov 8Nov 11Nov 15Nov 18Nov 22Nov 27Dec 4
28°FNov 10Nov 16Nov 20Nov 26Nov 30Dec 4Dec 14Dec 26Jan 4
24°FNov 26Dec 2Dec 8Dec 16Dec 28Jan 2Jan 6Jan 14Jan 27
20°FDec 8Dec 18Dec 28Jan 2Jan 6Jan 12Jan 17Jan 25Feb 2
16°FDec 23Jan 1Jan 3Jan 8Jan 14Jan 17Jan 22Jan 27Feb 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°F251242236231226220214210201
32°F283272263257252247241234225
28°F318307299292285277270262252
24°F358345336330321314305297281
20°F365365365365357347340332318
16°F365365365365365365365360343

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
91% of years
20°F or colder
57% of years
16°F or colder
23% 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
1,920
Cooling degree days, base 65°F
2,479
Growing degree days, base 40°F
9,731
Growing degree days, base 45°F
8,005
Growing degree days, base 50°F
6,396
Growing degree days, base 55°F
4,932
Growing degree days, base 60°F
3,620

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January5028112
February34815155
March20443320
April72101480
May9271727
June0439889
July0525990
August0521986
September2375823
October70141538
November27624229
December43715148

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 7.3 km from Petal. 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 USW00013833 (Hattiesburg Chain Muni AP). Public domain.