Brazos County climate

Brazos County Frost Dates and Growing Season

NOAA 1991-2020 normals for College Stn, 10 km from Brazos County, elevation 305 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for College Stn. 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 February 27 and the first fall freeze around November 30, a growing season of about 278 days.

Median at 36°F
last March 11, first November 17
Median at 32°F
last February 27, first November 30
Median at 28°F
last February 7, first December 18

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 2Mar 27Mar 20Mar 15Mar 11Mar 7Mar 3Feb 28Feb 22
32°FMar 18Mar 12Mar 6Mar 3Feb 27Feb 22Feb 16Feb 8Jan 31
28°FMar 9Mar 2Feb 24Feb 14Feb 7Jan 31Jan 25Jan 19Jan 6
24°FMar 1Feb 15Feb 7Jan 31Jan 23Jan 18Jan 10Jan 1Dec 21
20°FFeb 13Feb 4Jan 27Jan 21Jan 14Jan 6Jan 3Dec 30Dec 20
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 1Nov 6Nov 10Nov 14Nov 17Nov 21Nov 24Nov 29Dec 5
32°FNov 10Nov 17Nov 22Nov 26Nov 30Dec 3Dec 8Dec 15Dec 26
28°FNov 23Nov 30Dec 5Dec 10Dec 18Dec 25Jan 1Jan 8Jan 22
24°FDec 5Dec 13Dec 23Dec 31Jan 3Jan 10Jan 18Jan 27Feb 12
20°FDec 11Dec 22Dec 31Jan 2Jan 7Jan 16Jan 24Feb 1Feb 9
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°F280270262255250243238232223
32°F315303294285278272265257247
28°F353340331324316307299288274
24°F365365365361353343335325308
20°F365365365365365365365361340
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
100% of years
32°F or colder
100% of years
28°F or colder
95% of years
24°F or colder
66% of years
20°F or colder
25% of years
16°F or colder
6% 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
1,545
Cooling degree days, base 65°F
3,169
Growing degree days, base 40°F
10,783
Growing degree days, base 45°F
9,025
Growing degree days, base 50°F
7,355
Growing degree days, base 55°F
5,812
Growing degree days, base 60°F
4,411

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January43011141
February29322198
March15767389
April44154560
May3355817
June0528978
July06251,090
August06401,105
September1469918
October36224654
November19458336
December38718171

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 10 km from Brazos 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 USW00003904 (College Stn). Public domain.