Fillmore climate

Fillmore Frost Dates and Growing Season

NOAA 1991-2020 normals for Ojai, 28.9 km from Fillmore, elevation 745 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ojai. 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 21 and the first fall freeze around November 15, a growing season of about 235 days.

Median at 36°F
last April 19, first October 31
Median at 32°F
last March 21, first November 15
Median at 28°F
last February 17, 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°FMay 12May 1Apr 28Apr 23Apr 19Apr 15Apr 10Apr 7Mar 31
32°FApr 15Apr 8Apr 3Mar 29Mar 21Mar 14Mar 7Mar 1Feb 20
28°FMar 15Mar 3Feb 27Feb 23Feb 17Feb 10Feb 1Jan 21Jan 8
24°FFeb 19Feb 6Jan 29Jan 18Jan 11Jan 4Dec 30Dec 22Dec 12
20°FJan 25Jan 13Jan 9Jan 4Jan 2Dec 29Dec 25Dec 18Dec 11
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 14Oct 20Oct 23Oct 27Oct 31Nov 3Nov 6Nov 10Nov 15
32°FOct 28Nov 2Nov 7Nov 11Nov 15Nov 18Nov 21Nov 28Dec 2
28°FNov 12Nov 19Nov 23Nov 27Dec 1Dec 4Dec 9Dec 14Dec 22
24°FNov 28Dec 4Dec 9Dec 13Dec 17Dec 23Dec 30Jan 5Jan 22
20°FDec 9Dec 14Dec 19Dec 25Dec 31Jan 2Jan 6Jan 10Jan 24
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°F217209203198192188182176165
32°F270258249242235229223215206
28°F329313304295287280273262249
24°F365365359351343337330321307
20°F365365365365365365365365357
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
99% of years
24°F or colder
76% of years
20°F or colder
14% 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
2,516
Cooling degree days, base 65°F
761
Growing degree days, base 40°F
7,375
Growing degree days, base 45°F
5,594
Growing degree days, base 50°F
3,958
Growing degree days, base 55°F
2,575
Growing degree days, base 60°F
1,515

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January457070
February383085
March3341157
April2319233
May13432363
June4774477
July4204665
August3231693
September20159589
October11247400
November3034172
December488054

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 28.9 km from Fillmore. 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 USC00046399 (Ojai). Public domain.