Limestone County climate

Limestone County Frost Dates and Growing Season

NOAA 1991-2020 normals for Mexia, 14.7 km from Limestone County, elevation 503 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mexia. 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 13 and the first fall freeze around November 22, a growing season of about 251 days.

Median at 36°F
last March 29, first November 10
Median at 32°F
last March 13, first November 22
Median at 28°F
last February 28, 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 15Apr 8Apr 5Apr 1Mar 29Mar 24Mar 19Mar 14Mar 7
32°FApr 4Mar 29Mar 24Mar 19Mar 13Mar 10Mar 6Mar 1Feb 21
28°FMar 24Mar 15Mar 9Mar 4Feb 28Feb 23Feb 15Feb 5Jan 28
24°FMar 10Mar 2Feb 24Feb 14Feb 6Feb 1Jan 27Jan 19Jan 4
20°FMar 2Feb 16Feb 5Jan 31Jan 26Jan 19Jan 12Jan 4Dec 24
16°FFeb 14Feb 4Jan 29Jan 23Jan 17Jan 11Jan 8Jan 3Dec 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 28Nov 1Nov 4Nov 7Nov 10Nov 13Nov 18Nov 23Nov 29
32°FNov 4Nov 9Nov 13Nov 17Nov 22Nov 26Nov 30Dec 4Dec 10
28°FNov 11Nov 19Nov 25Nov 30Dec 4Dec 9Dec 16Dec 22Dec 30
24°FNov 22Dec 1Dec 9Dec 17Dec 24Dec 30Jan 3Jan 9Jan 21
20°FDec 3Dec 14Dec 27Jan 1Jan 3Jan 8Jan 15Jan 23Feb 6
16°FDec 11Dec 29Jan 2Jan 6Jan 9Jan 15Jan 21Feb 1Feb 9

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°F253245239233227223217212205
32°F279269262256251245239232223
28°F316304296288281273266257247
24°F357342334324314306297288274
20°F365365365360351342333323306
16°F365365365365365365365355337

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
93% of years
20°F or colder
64% 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
1,976
Cooling degree days, base 65°F
2,702
Growing degree days, base 40°F
9,917
Growing degree days, base 45°F
8,201
Growing degree days, base 50°F
6,589
Growing degree days, base 55°F
5,123
Growing degree days, base 60°F
3,823

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January533279
February3746126
March22427293
April7684459
May8260716
June0466916
July05911,055
August06211,086
September3430877
October46182604
November23730273
December4754105

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 14.7 km from Limestone County. 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 USC00415869 (Mexia). Public domain.