Friendswood climate

Friendswood Frost Dates and Growing Season

NOAA 1991-2020 normals for Houston Clover Fld, 4.1 km from Friendswood, elevation 44 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Houston Clover Fld. 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 January 31 and the first fall freeze around December 27, a growing season of about 328 days.

Median at 36°F
last February 21, first December 3
Median at 32°F
last January 31, first December 27
Median at 28°F
last January 18, first January 8

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 18Mar 10Mar 4Feb 27Feb 21Feb 16Feb 8Jan 31Jan 23
32°FMar 5Feb 24Feb 15Feb 6Jan 31Jan 27Jan 21Jan 12Jan 1
28°FFeb 20Feb 5Jan 30Jan 23Jan 18Jan 11Jan 7Jan 2Dec 22
24°FFeb 1Jan 21Jan 14Jan 10Jan 9Jan 7Jan 4Jan 2Dec 29
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 13Nov 19Nov 24Nov 29Dec 3Dec 7Dec 12Dec 23Jan 2
32°FNov 28Dec 5Dec 10Dec 20Dec 27Jan 1Jan 6Jan 12Jan 28
28°FDec 14Dec 24Dec 31Jan 3Jan 8Jan 12Jan 19Jan 28Feb 4
24°FDec 26Jan 1Jan 3Jan 6Jan 9Jan 10Jan 14Jan 20Feb 1
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°F324311303295287280272265252
32°F365351341334328320311301286
28°F365365365365365356347337325
24°F365365365365365365365365358
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
89% of years
28°F or colder
51% of years
24°F or colder
13% of years
20°F or colder
2% 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
1,074
Cooling degree days, base 65°F
3,394
Growing degree days, base 40°F
11,452
Growing degree days, base 45°F
9,650
Growing degree days, base 50°F
7,903
Growing degree days, base 55°F
6,257
Growing degree days, base 60°F
4,745

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January32121212
February20139276
March10394460
April24189615
May1396860
June05501,000
July06121,077
August06231,088
September0483933
October17268716
November12783411
December27935253

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 4.1 km from Friendswood. 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 USW00012975 (Houston Clover Fld). Public domain.