San Saba County climate

San Saba County Frost Dates and Growing Season

NOAA 1991-2020 normals for San Saba 7NW, 15.4 km from San Saba County, elevation 1330 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for San Saba 7NW. 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 16 and the first fall freeze around November 13, a growing season of about 239 days.

Median at 36°F
last April 1, first November 4
Median at 32°F
last March 16, first November 13
Median at 28°F
last March 4, first November 24

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 20Apr 15Apr 9Apr 5Apr 1Mar 29Mar 23Mar 17Mar 10
32°FApr 8Apr 1Mar 27Mar 21Mar 16Mar 12Mar 8Mar 3Feb 26
28°FMar 23Mar 15Mar 11Mar 7Mar 4Mar 1Feb 25Feb 20Feb 12
24°FMar 10Mar 5Mar 1Feb 25Feb 18Feb 13Feb 7Jan 31Jan 23
20°FMar 3Feb 22Feb 12Feb 5Jan 31Jan 25Jan 18Jan 6Dec 28
16°FFeb 15Feb 5Jan 30Jan 24Jan 19Jan 11Jan 5Dec 31Dec 23

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 23Oct 27Oct 31Nov 2Nov 4Nov 7Nov 10Nov 13Nov 18
32°FOct 30Nov 3Nov 7Nov 10Nov 13Nov 16Nov 19Nov 23Nov 29
28°FNov 6Nov 12Nov 17Nov 20Nov 24Nov 28Dec 1Dec 5Dec 13
24°FNov 17Nov 24Nov 29Dec 4Dec 8Dec 13Dec 19Dec 28Jan 5
20°FDec 1Dec 9Dec 15Dec 22Dec 28Jan 1Jan 5Jan 14Feb 1
16°FDec 13Dec 21Dec 28Jan 1Jan 5Jan 11Jan 18Jan 28Feb 5

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°F242233228223217212206201192
32°F265257251245239235229224214
28°F290282274269265259254248238
24°F330318311303296289281273261
20°F365359348340334326318306295
16°F365365365365365363353342329

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
100% of years
24°F or colder
100% of years
20°F or colder
86% of years
16°F or colder
48% 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
2,306
Cooling degree days, base 65°F
2,479
Growing degree days, base 40°F
9,414
Growing degree days, base 45°F
7,746
Growing degree days, base 50°F
6,205
Growing degree days, base 55°F
4,805
Growing degree days, base 60°F
3,559

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January586266
February4187118
March26624263
April9794453
May15266716
June0447897
July05631,028
August05731,038
September5347792
October80133522
November29822226
December542385

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 15.4 km from San Saba 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 USC00417994 (San Saba 7NW). Public domain.