Geronimo climate

Geronimo Frost Dates and Growing Season

NOAA 1991-2020 normals for Austin San Antonio, 7.4 km from Geronimo, elevation 633 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Austin San Antonio. 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 March 1 and the first fall freeze around November 26, a growing season of about 273 days.

Median at 36°F
last March 13, first November 15
Median at 32°F
last March 1, first November 26
Median at 28°F
last February 13, first December 11

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 3Mar 29Mar 23Mar 18Mar 13Mar 10Mar 6Mar 1Feb 23
32°FMar 20Mar 13Mar 8Mar 5Mar 1Feb 25Feb 21Feb 15Feb 3
28°FMar 10Mar 3Feb 26Feb 20Feb 13Feb 7Jan 30Jan 23Jan 11
24°FMar 1Feb 19Feb 8Feb 1Jan 26Jan 20Jan 10Jan 2Dec 23
20°FFeb 17Feb 4Jan 30Jan 22Jan 12Jan 6Jan 2Dec 29Dec 17
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°FOct 31Nov 4Nov 8Nov 11Nov 15Nov 18Nov 22Nov 26Dec 2
32°FNov 8Nov 14Nov 18Nov 22Nov 26Dec 1Dec 4Dec 9Dec 20
28°FNov 18Nov 27Dec 1Dec 6Dec 11Dec 19Dec 28Jan 4Jan 16
24°FDec 2Dec 10Dec 18Dec 26Jan 1Jan 4Jan 10Jan 22Feb 3
20°FDec 12Dec 22Dec 29Jan 1Jan 5Jan 9Jan 18Feb 1Feb 8
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°F273263257252246239233227219
32°F307295286279273266260253244
28°F346334323314306300289278267
24°F365365362353345336329318303
20°F365365365365365365365355341
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
97% of years
24°F or colder
74% of years
20°F or colder
34% 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
1,446
Cooling degree days, base 65°F
3,144
Growing degree days, base 40°F
10,850
Growing degree days, base 45°F
9,080
Growing degree days, base 50°F
7,389
Growing degree days, base 55°F
5,821
Growing degree days, base 60°F
4,400

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January40510150
February27525210
March14474405
April34176593
May3362825
June0522972
July06051,070
August06231,088
September1446896
October32226659
November18161348
December37215174

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 7.4 km from Geronimo. 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 USW00012971 (Austin San Antonio). Public domain.