Humble climate

Humble Frost Dates and Growing Season

NOAA 1991-2020 normals for Houston Intercont AP, 9.7 km from Humble, elevation 95 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Houston Intercont AP. 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 13 and the first fall freeze around December 9, a growing season of about 300 days.

Median at 36°F
last March 2, first November 25
Median at 32°F
last February 13, first December 9
Median at 28°F
last January 27, 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 25Mar 16Mar 11Mar 6Mar 2Feb 27Feb 23Feb 16Feb 5
32°FMar 12Mar 4Feb 28Feb 20Feb 13Feb 5Jan 31Jan 24Jan 12
28°FMar 2Feb 18Feb 6Feb 1Jan 27Jan 20Jan 14Jan 7Dec 26
24°FFeb 15Feb 3Jan 31Jan 24Jan 15Jan 10Jan 6Jan 1Dec 21
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 6Nov 12Nov 17Nov 21Nov 25Nov 29Dec 2Dec 6Dec 14
32°FNov 17Nov 25Dec 1Dec 4Dec 9Dec 15Dec 23Jan 1Jan 11
28°FDec 2Dec 11Dec 21Dec 29Jan 2Jan 6Jan 12Jan 20Feb 2
24°FDec 14Dec 28Jan 1Jan 4Jan 8Jan 12Jan 19Jan 30Feb 5
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°F296286277271266260253245234
32°F339326316307300292285275264
28°F365365360351343335329316301
24°F365365365365365365365353338
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
100% of years
32°F or colder
99% of years
28°F or colder
77% of years
24°F or colder
33% of years
20°F or colder
7% 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
1,266
Cooling degree days, base 65°F
3,288
Growing degree days, base 40°F
11,160
Growing degree days, base 45°F
9,375
Growing degree days, base 50°F
7,657
Growing degree days, base 55°F
6,054
Growing degree days, base 60°F
4,591

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January36617181
February23632244
March12385435
April31179599
May1384848
June0540990
July06231,088
August06251,090
September0465915
October27239678
November15870375
December32529217

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 9.7 km from Humble. 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 USW00012960 (Houston Intercont AP). Public domain.