Esparto climate

Esparto Frost Dates and Growing Season

NOAA 1991-2020 normals for Winters, 18.8 km from Esparto, elevation 135 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Winters. 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 18 and the first fall freeze around November 30, a growing season of about 284 days.

Median at 36°F
last March 18, first November 15
Median at 32°F
last February 18, first November 30
Median at 28°F
last January 14, 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 13Apr 5Mar 31Mar 25Mar 18Mar 14Mar 8Mar 2Feb 24
32°FMar 14Mar 7Mar 1Feb 25Feb 18Feb 12Feb 6Jan 30Jan 17
28°FFeb 17Feb 3Jan 27Jan 20Jan 14Jan 8Jan 1Dec 28Dec 18
24°FJan 22Jan 15Jan 10Jan 5Dec 31Dec 30Dec 26Dec 19Dec 10
20°F–––––––––
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 2Nov 7Nov 10Nov 13Nov 15Nov 17Nov 20Nov 24Nov 29
32°FNov 15Nov 20Nov 23Nov 26Nov 30Dec 2Dec 6Dec 10Dec 18
28°FNov 28Dec 2Dec 6Dec 11Dec 15Dec 19Dec 26Jan 3Jan 12
24°FDec 4Dec 9Dec 15Dec 21Dec 27Dec 30Jan 2Jan 9Jan 16
20°F–––––––––
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°F271261252246240234227221211
32°F322311300291284278271264253
28°F365356348342336332325317302
24°F365365365365365365359352341
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
87% of years
24°F or colder
37% of years
20°F or colder
6% 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
2,392
Cooling degree days, base 65°F
1,541
Growing degree days, base 40°F
8,283
Growing degree days, base 45°F
6,522
Growing degree days, base 50°F
4,933
Growing degree days, base 55°F
3,587
Growing degree days, base 60°F
2,461

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January558021
February385077
March2845200
April15429328
May50134549
June6276720
July0385849
August0361826
September4266712
October7283476
November3232152
December556023

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 18.8 km from Esparto. 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 USC00049742 (Winters). Public domain.