Walthall County climate

Walthall County Frost Dates and Growing Season

NOAA 1991-2020 normals for Tylertown 5ESE, 8.7 km from Walthall County, elevation 382 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tylertown 5ESE. 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 15 and the first fall freeze around November 16, a growing season of about 245 days.

Median at 36°F
last March 31, first November 4
Median at 32°F
last March 15, first November 16
Median at 28°F
last February 28, first December 1

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 13Apr 8Apr 4Mar 31Mar 27Mar 22Mar 16Mar 7
32°FApr 8Apr 1Mar 26Mar 21Mar 15Mar 11Mar 5Feb 28Feb 20
28°FMar 24Mar 16Mar 11Mar 5Feb 28Feb 25Feb 19Feb 12Jan 31
24°FMar 11Mar 4Feb 26Feb 21Feb 14Feb 7Jan 31Jan 26Jan 11
20°FMar 2Feb 20Feb 10Feb 2Jan 29Jan 23Jan 15Jan 7Dec 29
16°FFeb 17Feb 4Jan 30Jan 25Jan 19Jan 11Jan 6Dec 31Dec 24

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 22Oct 27Oct 30Nov 1Nov 4Nov 7Nov 12Nov 16Nov 22
32°FOct 31Nov 3Nov 7Nov 12Nov 16Nov 20Nov 23Nov 30Dec 5
28°FNov 7Nov 14Nov 20Nov 26Dec 1Dec 4Dec 9Dec 16Dec 31
24°FNov 24Dec 2Dec 6Dec 12Dec 20Dec 29Jan 2Jan 9Jan 20
20°FDec 7Dec 18Dec 26Dec 31Jan 3Jan 7Jan 13Jan 21Feb 3
16°FDec 17Dec 26Jan 1Jan 4Jan 8Jan 13Jan 20Jan 29Feb 4

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°F248239230224220214209204196
32°F277265257250245239233226216
28°F310299290282274268260252241
24°F346334325315309302295285272
20°F365365362353343334326314301
16°F365365365365365365358342327

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
97% of years
20°F or colder
77% of years
16°F or colder
41% 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
1,967
Cooling degree days, base 65°F
2,347
Growing degree days, base 40°F
9,565
Growing degree days, base 45°F
7,846
Growing degree days, base 50°F
6,237
Growing degree days, base 55°F
4,774
Growing degree days, base 60°F
3,471

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January5094101
February3719135
March21733303
April8888453
May10250705
June0424874
July0495959
August0505970
September2361808
October68142543
November26028251
December4439136

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 8.7 km from Walthall County. 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 USC00229048 (Tylertown 5ESE). Public domain.