Willits climate

Willits Frost Dates and Growing Season

NOAA 1991-2020 normals for Willits 1 Ne, 1.6 km from Willits, elevation 1353 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Willits 1 Ne. 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 5 and the first fall freeze around October 9, a growing season of about 157 days.

Median at 36°F
last June 1, first September 20
Median at 32°F
last May 5, first October 9
Median at 28°F
last March 31, first October 30

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 23Jun 16Jun 9Jun 5Jun 1May 30May 25May 20May 14
32°FMay 31May 23May 17May 11May 5May 1Apr 27Apr 21Apr 11
28°FApr 23Apr 15Apr 9Apr 4Mar 31Mar 24Mar 13Mar 5Feb 18
24°FMar 26Mar 12Mar 1Feb 22Feb 11Jan 31Jan 15Jan 1Dec 20
20°FFeb 12Jan 31Jan 21Jan 5Dec 31Dec 25Dec 17Dec 7Nov 29
16°FJan 21Jan 5Dec 31Dec 29Dec 21Dec 15Dec 10Dec 6Dec 1

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 1Sep 7Sep 11Sep 16Sep 20Sep 24Sep 28Oct 2Oct 7
32°FSep 24Sep 30Oct 3Oct 5Oct 9Oct 13Oct 18Oct 23Oct 31
28°FOct 8Oct 14Oct 20Oct 25Oct 30Nov 2Nov 10Nov 18Nov 30
24°FOct 25Nov 2Nov 10Nov 19Nov 26Dec 1Dec 9Dec 16Jan 1
20°FNov 15Nov 27Dec 2Dec 7Dec 14Dec 21Dec 30Jan 8Jan 30
16°FDec 1Dec 4Dec 8Dec 12Dec 16Dec 22Dec 30Jan 2Jan 19

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°F134124118112107102968980
32°F187177169162157151145137128
28°F262244232224216206199189178
24°F342327314304293283269254238
20°F365365365365357343334326312
16°F365365365365365365365365354

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
94% of years
20°F or colder
56% of years
16°F or colder
13% 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
4,527
Cooling degree days, base 65°F
195
Growing degree days, base 40°F
4,875
Growing degree days, base 45°F
3,324
Growing degree days, base 50°F
2,093
Growing degree days, base 55°F
1,185
Growing degree days, base 60°F
556

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January66705
February554017
March550038
April464066
May3284164
June17823298
July5780488
August7053448
September12030361
October3243166
November522038
December69305

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 1.6 km from Willits. 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 USC00049684 (Willits 1 Ne). Public domain.