Conroe climate

Conroe Frost Dates and Growing Season

NOAA 1991-2020 normals for Conroe, 3.3 km from Conroe, elevation 245 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Conroe. 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 24 and the first fall freeze around December 2, a growing season of about 285 days.

Median at 36°F
last March 9, first November 20
Median at 32°F
last February 24, first December 2
Median at 28°F
last February 2, first December 23

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 31Mar 24Mar 19Mar 14Mar 9Mar 5Mar 1Feb 25Feb 16
32°FMar 17Mar 9Mar 4Feb 28Feb 24Feb 17Feb 9Feb 2Jan 26
28°FMar 6Feb 28Feb 19Feb 9Feb 2Jan 28Jan 21Jan 12Dec 31
24°FMar 1Feb 16Feb 5Jan 31Jan 22Jan 16Jan 9Jan 2Dec 26
20°FFeb 19Feb 5Jan 30Jan 18Jan 12Jan 7Jan 5Jan 1Dec 28
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 2Nov 7Nov 12Nov 16Nov 20Nov 24Nov 28Dec 2Dec 8
32°FNov 11Nov 17Nov 24Nov 29Dec 2Dec 6Dec 13Dec 21Jan 2
28°FNov 24Dec 1Dec 7Dec 15Dec 23Jan 1Jan 4Jan 10Jan 28
24°FDec 7Dec 22Dec 29Jan 2Jan 5Jan 9Jan 16Jan 30Feb 13
20°FDec 26Dec 30Jan 2Jan 4Jan 7Jan 12Jan 19Feb 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°F284274267261254248242236226
32°F324310301292285277271262253
28°F365348337330321312304296280
24°F365365365365359350339328311
20°F365365365365365365365365345
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
93% of years
24°F or colder
58% of years
20°F or colder
21% of years
16°F or colder
4% 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
1,440
Cooling degree days, base 65°F
3,172
Growing degree days, base 40°F
10,883
Growing degree days, base 45°F
9,118
Growing degree days, base 50°F
7,434
Growing degree days, base 55°F
5,869
Growing degree days, base 60°F
4,441

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January40814156
February26925218
March14374409
April39168580
May3363825
June0523973
July06091,074
August06231,088
September1457906
October36230660
November17765355
December36521190

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 3.3 km from Conroe. 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 USC00411956 (Conroe). Public domain.