Purvis climate

Purvis Frost Dates and Growing Season

NOAA 1991-2020 normals for Hattiesburg 5SW, 14.1 km from Purvis, elevation 385 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hattiesburg 5SW. 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 7 and the first fall freeze around November 23, a growing season of about 261 days.

Median at 36°F
last March 23, first November 11
Median at 32°F
last March 7, first November 23
Median at 28°F
last February 20, first December 4

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 12Apr 5Mar 31Mar 26Mar 23Mar 18Mar 13Mar 8Mar 2
32°FMar 26Mar 20Mar 15Mar 11Mar 7Mar 2Feb 27Feb 22Feb 14
28°FMar 16Mar 8Mar 3Feb 26Feb 20Feb 15Feb 8Feb 1Jan 26
24°FMar 7Feb 28Feb 20Feb 11Feb 4Jan 31Jan 26Jan 18Jan 4
20°FFeb 26Feb 15Feb 3Jan 31Jan 26Jan 20Jan 13Jan 4Dec 30
16°FFeb 18Feb 3Jan 30Jan 25Jan 20Jan 15Jan 8Jan 3Dec 28

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 27Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 22Nov 29
32°FNov 5Nov 10Nov 15Nov 19Nov 23Nov 27Dec 1Dec 5Dec 14
28°FNov 14Nov 21Nov 27Dec 1Dec 4Dec 11Dec 19Dec 29Jan 6
24°FDec 1Dec 7Dec 15Dec 23Dec 30Jan 2Jan 7Jan 15Jan 28
20°FDec 14Dec 25Dec 31Jan 2Jan 6Jan 12Jan 17Jan 25Feb 5
16°FDec 25Jan 1Jan 3Jan 6Jan 12Jan 16Jan 23Jan 30Feb 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°F260250244237233228222217208
32°F290279272266261255249243234
28°F325313306300291284276268259
24°F361345337332323315306299288
20°F365365365365355346337331314
16°F365365365365365365365357340

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
99% of years
24°F or colder
89% of years
20°F or colder
61% of years
16°F or colder
28% 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
1,922
Cooling degree days, base 65°F
2,440
Growing degree days, base 40°F
9,708
Growing degree days, base 45°F
7,990
Growing degree days, base 50°F
6,381
Growing degree days, base 55°F
4,908
Growing degree days, base 60°F
3,586

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January5095107
February35811149
March20939318
April76100476
May9266722
June0438888
July0512977
August0510975
September2373822
October65148551
November25227255
December44310141

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 14.1 km from Purvis. 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 USC00223887 (Hattiesburg 5SW). Public domain.