Mathis climate

Mathis Frost Dates and Growing Season

NOAA 1991-2020 normals for Mathis 4 Ssw, 7.8 km from Mathis, elevation 138 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mathis 4 Ssw. 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 January 31 and the first fall freeze around December 23, a growing season of about 328 days.

Median at 36°F
last February 21, first December 4
Median at 32°F
last January 31, first December 23
Median at 28°F
last January 13, first January 2

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°FMar 16Mar 8Mar 3Feb 28Feb 21Feb 16Feb 9Jan 31Jan 20
32°FMar 4Feb 25Feb 15Feb 7Jan 31Jan 25Jan 15Jan 4Dec 22
28°FFeb 20Feb 8Jan 31Jan 23Jan 13Jan 7Jan 2Dec 27Dec 16
24°FFeb 14Jan 31Jan 19Jan 12Jan 7Jan 2Dec 31Dec 24Dec 18
20°F–––––––––
16°F–––––––––

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°FNov 14Nov 20Nov 25Nov 30Dec 4Dec 7Dec 12Dec 20Jan 2
32°FNov 28Dec 4Dec 9Dec 15Dec 23Dec 29Jan 3Jan 11Jan 28
28°FDec 7Dec 15Dec 23Dec 29Jan 2Jan 6Jan 15Jan 25Feb 7
24°FDec 14Dec 22Dec 29Jan 1Jan 3Jan 8Jan 16Jan 25Feb 11
20°F–––––––––
16°F–––––––––

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°F324311305297289282274266255
32°F365351342334328320310301288
28°F365365365365363354343333317
24°F365365365365365365365365352
20°F365365365365365365365365365
16°F365365365365365365365365365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
99% of years
32°F or colder
89% of years
28°F or colder
50% of years
24°F or colder
16% of years
20°F or colder
2% of years
16°F or colder
0% 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
1,078
Cooling degree days, base 65°F
3,323
Growing degree days, base 40°F
11,381
Growing degree days, base 45°F
9,588
Growing degree days, base 50°F
7,846
Growing degree days, base 55°F
6,200
Growing degree days, base 60°F
4,684

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January32619209
February20541280
March101102474
April23200628
May1384848
June0523973
July05841,049
August06091,074
September0462912
October19273720
November12291427
December28133253

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 7.8 km from Mathis. 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 USC00415661 (Mathis 4 Ssw). Public domain.