Cloverdale climate

Cloverdale Frost Dates and Growing Season

NOAA 1991-2020 normals for Greencastle 1 W, 16 km from Cloverdale, elevation 735 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Greencastle 1 W. 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 April 27 and the first fall freeze around October 15, a growing season of about 169 days.

Median at 36°F
last May 8, first October 4
Median at 32°F
last April 27, first October 15
Median at 28°F
last April 15, first October 26

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 25May 20May 16May 12May 8May 5May 2Apr 28Apr 23
32°FMay 15May 8May 3Apr 30Apr 27Apr 24Apr 20Apr 17Apr 13
28°FMay 2Apr 26Apr 22Apr 18Apr 15Apr 11Apr 8Apr 5Mar 31
24°FApr 19Apr 13Apr 8Apr 5Apr 2Mar 31Mar 28Mar 24Mar 18
20°FApr 8Apr 2Mar 30Mar 27Mar 24Mar 20Mar 16Mar 11Mar 4
16°FMar 29Mar 23Mar 18Mar 15Mar 11Mar 8Mar 4Feb 28Feb 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°FSep 23Sep 27Sep 30Oct 2Oct 4Oct 7Oct 9Oct 12Oct 16
32°FOct 1Oct 5Oct 9Oct 12Oct 15Oct 17Oct 19Oct 22Oct 26
28°FOct 12Oct 17Oct 21Oct 23Oct 26Oct 28Oct 30Nov 1Nov 5
24°FOct 24Oct 29Nov 1Nov 2Nov 4Nov 7Nov 11Nov 14Nov 20
20°FNov 2Nov 5Nov 8Nov 12Nov 15Nov 19Nov 23Nov 28Dec 2
16°FNov 8Nov 14Nov 18Nov 22Nov 26Nov 30Dec 3Dec 8Dec 15

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°F167161156152149145140136128
32°F188181177173169165161156149
28°F211205201196191187183178171
24°F238230224220216212209204196
20°F263254248243239233229223217
16°F284275269264259254249241233

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
5,973
Cooling degree days, base 65°F
733
Growing degree days, base 40°F
5,285
Growing degree days, base 45°F
4,107
Growing degree days, base 50°F
3,059
Growing degree days, base 55°F
2,142
Growing degree days, base 60°F
1,358

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22003
February99503
March793140
April4466124
May18850340
June34162579
July7230688
August12192645
September9881437
October38911166
November732031
December1,06005

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 16 km from Cloverdale. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00123513 (Greencastle 1 W). Public domain.