Chatom climate

Chatom Frost Dates and Growing Season

NOAA 1991-2020 normals for Chatom, 0.8 km from Chatom, elevation 285 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chatom. 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 26 and the first fall freeze around November 8, a growing season of about 228 days.

Median at 36°F
last April 8, first October 29
Median at 32°F
last March 26, first November 8
Median at 28°F
last March 10, first November 20

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 24Apr 19Apr 15Apr 11Apr 8Apr 5Apr 2Mar 28Mar 21
32°FApr 11Apr 6Apr 3Mar 30Mar 26Mar 23Mar 18Mar 13Mar 3
28°FMar 31Mar 24Mar 19Mar 15Mar 10Mar 5Feb 28Feb 25Feb 17
24°FMar 17Mar 9Mar 4Feb 28Feb 24Feb 18Feb 13Feb 5Jan 27
20°FMar 3Feb 24Feb 17Feb 10Feb 4Jan 30Jan 24Jan 14Jan 1
16°FFeb 18Feb 7Feb 2Jan 30Jan 24Jan 17Jan 12Jan 4Dec 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 15Oct 20Oct 24Oct 26Oct 29Nov 1Nov 3Nov 6Nov 12
32°FOct 25Oct 30Nov 1Nov 5Nov 8Nov 11Nov 15Nov 20Nov 27
28°FNov 2Nov 7Nov 12Nov 16Nov 20Nov 25Nov 30Dec 4Dec 12
24°FNov 11Nov 19Nov 25Dec 1Dec 4Dec 9Dec 16Dec 27Jan 6
20°FNov 25Dec 4Dec 12Dec 21Dec 29Jan 2Jan 7Jan 14Jan 30
16°FDec 9Dec 23Dec 30Jan 3Jan 8Jan 13Jan 20Jan 28Feb 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°F227219213208204200196191184
32°F254245239233228222217211203
28°F287275267261255249244237227
24°F321309302294287280273263253
20°F365351341332324315308299286
16°F365365365365359350339332319

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
91% of years
16°F or colder
57% 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
2,306
Cooling degree days, base 65°F
2,100
Growing degree days, base 40°F
9,011
Growing degree days, base 45°F
7,330
Growing degree days, base 50°F
5,782
Growing degree days, base 55°F
4,384
Growing degree days, base 60°F
3,152

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January571383
February4096115
March26424260
April10667414
May19225671
June0392841
July0481945
August0464928
September4317763
October97101473
November32216193
December514495

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 0.8 km from Chatom. 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 USC00011566 (Chatom). Public domain.