Santa Anna climate

Santa Anna Frost Dates and Growing Season

NOAA 1991-2020 normals for Coleman, 14.1 km from Santa Anna, elevation 1718 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Coleman. 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 14 and the first fall freeze around November 20, a growing season of about 249 days.

Median at 36°F
last March 30, first November 8
Median at 32°F
last March 14, first November 20
Median at 28°F
last March 1, first December 1

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 15Apr 8Apr 5Apr 2Mar 30Mar 25Mar 20Mar 15Mar 8
32°FApr 2Mar 28Mar 23Mar 18Mar 14Mar 9Mar 5Mar 2Feb 25
28°FMar 21Mar 14Mar 8Mar 4Mar 1Feb 26Feb 21Feb 16Feb 5
24°FMar 8Mar 2Feb 26Feb 19Feb 13Feb 6Jan 31Jan 24Jan 6
20°FFeb 27Feb 16Feb 8Feb 1Jan 28Jan 21Jan 13Jan 3Dec 22
16°FFeb 13Feb 6Feb 1Jan 26Jan 22Jan 15Jan 5Dec 30Dec 20

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 26Nov 1Nov 3Nov 5Nov 8Nov 11Nov 16Nov 21Nov 27
32°FNov 2Nov 7Nov 11Nov 16Nov 20Nov 23Nov 27Dec 1Dec 7
28°FNov 11Nov 19Nov 24Nov 29Dec 1Dec 4Dec 9Dec 14Dec 22
24°FNov 25Dec 1Dec 7Dec 12Dec 17Dec 23Dec 30Jan 5Jan 16
20°FDec 6Dec 14Dec 21Dec 28Jan 2Jan 8Jan 15Jan 24Feb 5
16°FDec 15Dec 23Dec 30Jan 4Jan 11Jan 19Jan 24Feb 1Feb 6

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°F250242237232227222216210203
32°F275266260254249244239233225
28°F310298291284277271265257247
24°F347334325317309302295286276
20°F365365365354345337329319305
16°F365365365365365365363349334

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
98% of years
20°F or colder
74% of years
16°F or colder
37% 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
2,162
Cooling degree days, base 65°F
2,670
Growing degree days, base 40°F
9,745
Growing degree days, base 45°F
8,058
Growing degree days, base 50°F
6,485
Growing degree days, base 55°F
5,057
Growing degree days, base 60°F
3,781

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January558278
February4017126
March24834289
April78116492
May12294747
June0482931
July06011,066
August05921,057
September4371818
October70145544
November27924242
December512295

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 14.1 km from Santa Anna. 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 USC00411875 (Coleman). Public domain.