Selma climate

Selma Frost Dates and Growing Season

NOAA 1991-2020 normals for New Braunfels, 16.1 km from Selma, elevation 720 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for New Braunfels. 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 8 and the first fall freeze around November 18, a growing season of about 253 days.

Median at 36°F
last March 25, first November 7
Median at 32°F
last March 8, first November 18
Median at 28°F
last February 24, first December 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°FApr 18Apr 8Apr 3Mar 31Mar 25Mar 19Mar 14Mar 7Feb 28
32°FApr 1Mar 24Mar 18Mar 13Mar 8Mar 3Feb 28Feb 23Feb 17
28°FMar 17Mar 10Mar 5Feb 28Feb 24Feb 20Feb 14Feb 7Jan 29
24°FMar 8Mar 1Feb 22Feb 14Feb 7Feb 1Jan 27Jan 16Jan 3
20°FMar 1Feb 15Feb 6Jan 31Jan 23Jan 16Jan 9Jan 2Dec 25
16°FFeb 14Feb 5Jan 29Jan 21Jan 17Jan 12Jan 8Jan 5Jan 1

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 25Oct 29Nov 1Nov 4Nov 7Nov 10Nov 13Nov 18Nov 25
32°FNov 2Nov 6Nov 10Nov 14Nov 18Nov 22Nov 27Dec 1Dec 10
28°FNov 10Nov 17Nov 23Nov 29Dec 2Dec 6Dec 15Dec 28Jan 8
24°FNov 27Dec 3Dec 10Dec 18Dec 28Jan 1Jan 8Jan 17Feb 2
20°FDec 8Dec 19Dec 27Jan 1Jan 6Jan 10Jan 17Jan 28Feb 10
16°FDec 31Jan 2Jan 6Jan 8Jan 12Jan 17Jan 22Feb 1Feb 12

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°F256247240233227221215208200
32°F287275266259253247241234223
28°F319308299293284276269262251
24°F364345334326318309303294281
20°F365365365365358346337328307
16°F365365365365365365365363344

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
91% of years
20°F or colder
60% of years
16°F or colder
21% 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
1,831
Cooling degree days, base 65°F
2,632
Growing degree days, base 40°F
9,973
Growing degree days, base 45°F
8,238
Growing degree days, base 50°F
6,606
Growing degree days, base 55°F
5,117
Growing degree days, base 60°F
3,786

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4915102
February34510153
March19447336
April72119499
May9299755
June0453903
July05501,015
August05561,021
September2380828
October58166575
November23636280
December42511139

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 16.1 km from Selma. 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 USC00416276 (New Braunfels). Public domain.