Tehachapi climate

Tehachapi Frost Dates and Growing Season

NOAA 1991-2020 normals for Tehachapi 4 Se, 4.2 km from Tehachapi, elevation 4220 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tehachapi 4 Se. 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 April 28 and the first fall freeze around October 26, a growing season of about 183 days.

Median at 36°F
last May 16, first October 10
Median at 32°F
last April 28, first October 26
Median at 28°F
last April 12, first November 16

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°FJun 5May 31May 25May 20May 16May 11May 7May 3Apr 27
32°FMay 21May 11May 5May 1Apr 28Apr 25Apr 21Apr 18Apr 11
28°FApr 30Apr 24Apr 20Apr 16Apr 12Apr 7Apr 2Mar 25Mar 14
24°FApr 14Apr 6Mar 30Mar 22Mar 14Mar 7Mar 1Feb 21Feb 10
20°FMar 20Mar 5Feb 26Feb 19Feb 12Feb 3Jan 26Jan 10Dec 24
16°FFeb 28Feb 21Feb 12Feb 3Jan 24Jan 11Jan 3Dec 27Dec 14

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°FSep 26Sep 30Oct 2Oct 6Oct 10Oct 14Oct 19Oct 24Nov 1
32°FOct 4Oct 11Oct 17Oct 22Oct 26Nov 1Nov 4Nov 10Nov 17
28°FOct 22Nov 1Nov 5Nov 10Nov 16Nov 21Nov 26Dec 1Dec 5
24°FNov 9Nov 20Nov 27Dec 1Dec 4Dec 7Dec 11Dec 16Dec 23
20°FDec 1Dec 7Dec 11Dec 17Dec 23Dec 29Jan 3Jan 22Feb 8
16°FDec 8Dec 13Dec 24Dec 30Jan 3Jan 13Jan 26Feb 9Feb 22

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°F176166159154149143137130122
32°F209201194189183177170162154
28°F250239231225218212207199187
24°F300287277270263253245236225
20°F360344333322313305296285268
16°F365365365365363352342327309

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
91% of years
16°F or colder
54% 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
4,443
Cooling degree days, base 65°F
631
Growing degree days, base 40°F
5,563
Growing degree days, base 45°F
4,115
Growing degree days, base 50°F
2,922
Growing degree days, base 55°F
1,972
Growing degree days, base 60°F
1,217

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January72108
February64509
March609029
April488070
May27718235
June7691467
July5220680
August6203662
September7290470
October2699227
November525059
December75007

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 4.2 km from Tehachapi. 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 USC00048829 (Tehachapi 4 Se). Public domain.