Martindale climate

Martindale Frost Dates and Growing Season

NOAA 1991-2020 normals for San Marcos, 11.2 km from Martindale, elevation 665 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for San Marcos. 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 28 and the first fall freeze around November 29, a growing season of about 273 days.

Median at 36°F
last March 14, first November 16
Median at 32°F
last February 28, first November 29
Median at 28°F
last February 13, first December 15

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 5Mar 31Mar 24Mar 19Mar 14Mar 9Mar 5Feb 28Feb 23
32°FMar 21Mar 14Mar 8Mar 4Feb 28Feb 25Feb 20Feb 14Feb 1
28°FMar 8Mar 1Feb 25Feb 20Feb 13Feb 6Jan 31Jan 25Jan 9
24°FFeb 28Feb 15Feb 8Feb 2Jan 29Jan 23Jan 17Jan 5Dec 26
20°FFeb 13Feb 5Jan 30Jan 23Jan 19Jan 10Jan 5Dec 31Dec 25
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 1Nov 5Nov 8Nov 12Nov 16Nov 19Nov 23Nov 29Dec 4
32°FNov 8Nov 14Nov 19Nov 25Nov 29Dec 2Dec 6Dec 12Dec 21
28°FNov 19Nov 29Dec 3Dec 8Dec 15Dec 21Dec 28Jan 3Jan 13
24°FDec 5Dec 14Dec 21Dec 29Jan 2Jan 6Jan 13Jan 23Feb 5
20°FDec 19Dec 25Dec 31Jan 3Jan 7Jan 14Jan 22Feb 1Feb 10
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°F272263257252246241234227218
32°F307295286279273267259252243
28°F345333322314306298290280270
24°F365365362351343334325315302
20°F365365365365365365365354337
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
98% of years
24°F or colder
75% of years
20°F or colder
33% of years
16°F or colder
9% 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
1,620
Cooling degree days, base 65°F
2,974
Growing degree days, base 40°F
10,508
Growing degree days, base 45°F
8,754
Growing degree days, base 50°F
7,089
Growing degree days, base 55°F
5,558
Growing degree days, base 60°F
4,183

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4526115
February30814175
March16752365
April43135542
May4331792
June0511961
July06061,071
August06281,093
September1436885
October41199625
November19946319
December40510145

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 11.2 km from Martindale. 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 USC00417983 (San Marcos). Public domain.