Waller County climate

Waller County Frost Dates and Growing Season

NOAA 1991-2020 normals for Bellville 6NNE, 22.1 km from Waller County, elevation 280 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bellville 6NNE. 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 28 and the first fall freeze around December 2, a growing season of about 279 days.

Median at 36°F
last March 12, first November 19
Median at 32°F
last February 28, first December 2
Median at 28°F
last February 11, first December 16

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 21Mar 17Mar 12Mar 8Mar 4Feb 28Feb 21
32°FMar 20Mar 13Mar 8Mar 3Feb 28Feb 23Feb 18Feb 11Jan 31
28°FMar 9Mar 2Feb 24Feb 18Feb 11Feb 4Jan 30Jan 22Jan 10
24°FMar 1Feb 14Feb 4Jan 30Jan 25Jan 18Jan 11Jan 2Dec 22
20°FFeb 10Feb 2Jan 27Jan 21Jan 18Jan 9Jan 4Dec 31Dec 19
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 8Nov 12Nov 16Nov 19Nov 24Nov 27Dec 1Dec 6
32°FNov 12Nov 18Nov 23Nov 28Dec 2Dec 5Dec 10Dec 16Dec 25
28°FNov 23Dec 1Dec 5Dec 10Dec 16Dec 24Dec 31Jan 5Jan 15
24°FDec 6Dec 13Dec 22Dec 29Jan 1Jan 6Jan 12Jan 19Feb 3
20°FDec 14Dec 24Dec 31Jan 1Jan 6Jan 9Jan 17Jan 21Feb 2
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°F277269262257253247242236226
32°F309300292285279274267259249
28°F349335327318311304296288278
24°F365365363355347339331320306
20°F365365365365365365365358340
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
96% of years
24°F or colder
74% of years
20°F or colder
31% of years
16°F or colder
7% 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
1,559
Cooling degree days, base 65°F
2,956
Growing degree days, base 40°F
10,564
Growing degree days, base 45°F
8,818
Growing degree days, base 50°F
7,160
Growing degree days, base 55°F
5,613
Growing degree days, base 60°F
4,204

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January44811139
February30120197
March15565389
April47143548
May5330790
June0493943
July05811,046
August05901,055
September0426876
October35213644
November17367361
December39616171

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 22.1 km from Waller County. 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 USC00410655 (Bellville 6NNE). Public domain.