Hesperia climate

Hesperia Frost Dates and Growing Season

NOAA 1991-2020 normals for Hesperia 2E, 3.3 km from Hesperia, elevation 3055 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hesperia 2E. 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 December 1, a growing season of about 270 days.

Median at 36°F
last March 31, first November 16
Median at 32°F
last February 28, first December 1
Median at 28°F
last January 30, first December 14

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 22Apr 13Apr 9Apr 5Mar 31Mar 25Mar 19Mar 11Mar 3
32°FApr 3Mar 22Mar 12Mar 5Feb 28Feb 24Feb 17Feb 11Feb 1
28°FMar 1Feb 21Feb 12Feb 5Jan 30Jan 23Jan 15Jan 8Dec 31
24°FFeb 7Jan 28Jan 20Jan 14Jan 8Jan 3Dec 31Dec 25Dec 15
20°FJan 15Jan 11Jan 6Jan 3Dec 31Dec 31Dec 26Dec 18Dec 9
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 29Nov 4Nov 9Nov 12Nov 16Nov 20Nov 24Nov 27Dec 1
32°FNov 11Nov 18Nov 23Nov 28Dec 1Dec 4Dec 7Dec 11Dec 16
28°FNov 26Dec 2Dec 7Dec 10Dec 14Dec 19Dec 24Dec 29Jan 10
24°FDec 8Dec 13Dec 20Dec 25Dec 28Jan 1Jan 5Jan 14Jan 25
20°FDec 9Dec 13Dec 24Dec 29Dec 31Jan 2Jan 5Jan 9Jan 13
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°F259247241235229223216210199
32°F304293285278270263255247236
28°F350340333325318310303294281
24°F365365365365361354348340330
20°F365365365365365365365365365
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
57% of years
20°F or colder
10% of years
16°F or colder
0% 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
2,414
Cooling degree days, base 65°F
1,924
Growing degree days, base 40°F
8,660
Growing degree days, base 45°F
6,934
Growing degree days, base 50°F
5,367
Growing degree days, base 55°F
4,005
Growing degree days, base 60°F
2,857

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January515048
February410087
March3024195
April16727316
May62137540
June7322765
July0493958
August0496961
September6340784
October7299492
November3197174
December555046

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 3.3 km from Hesperia. 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 USC00043937 (Hesperia 2E). Public domain.