Fillmore climate

Fillmore Frost Dates and Growing Season

NOAA 1991-2020 normals for Fillmore, 1 km from Fillmore, elevation 5127 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fillmore. 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 May 4 and the first fall freeze around October 14, a growing season of about 160 days.

Median at 36°F
last May 20, first October 2
Median at 32°F
last May 4, first October 14
Median at 28°F
last April 19, first October 25

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 8Jun 1May 28May 24May 20May 15May 12May 7May 1
32°FMay 26May 18May 12May 8May 4May 1Apr 28Apr 24Apr 18
28°FMay 9May 2Apr 27Apr 23Apr 19Apr 15Apr 10Apr 5Mar 30
24°FApr 21Apr 13Apr 7Apr 3Mar 30Mar 25Mar 19Mar 12Mar 6
20°FApr 1Mar 23Mar 17Mar 12Mar 8Mar 5Mar 1Feb 25Feb 17
16°FMar 11Mar 4Feb 28Feb 25Feb 21Feb 18Feb 14Feb 10Feb 2

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 20Sep 24Sep 27Sep 30Oct 2Oct 5Oct 8Oct 13Oct 17
32°FSep 30Oct 3Oct 7Oct 10Oct 14Oct 16Oct 19Oct 23Oct 28
28°FOct 9Oct 15Oct 18Oct 22Oct 25Oct 28Oct 31Nov 3Nov 8
24°FOct 19Oct 25Oct 29Nov 1Nov 5Nov 7Nov 11Nov 15Nov 19
20°FOct 29Nov 3Nov 7Nov 12Nov 15Nov 18Nov 21Nov 25Nov 29
16°FNov 8Nov 14Nov 18Nov 22Nov 25Nov 28Dec 1Dec 6Dec 11

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°F158151145139135130124119110
32°F182175169165160155150143133
28°F214204197191186182176171162
24°F246238230224219213207200190
20°F273265259255250245240234224
16°F299290283278273269263257249

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
100% of years
16°F or colder
100% 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
5,769
Cooling degree days, base 65°F
799
Growing degree days, base 40°F
5,231
Growing degree days, base 45°F
4,036
Growing degree days, base 50°F
3,004
Growing degree days, base 55°F
2,126
Growing degree days, base 60°F
1,393

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,09900
February84801
March667027
April469293
May23429284
June58140534
July3294756
August5254714
September9476437
October4124144
November773015
December1,11000

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 1 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 USC00422828 (Fillmore). Public domain.