Smith River climate

Smith River Frost Dates and Growing Season

NOAA 1991-2020 normals for Crescent City 3 Nnw, 15.7 km from Smith River, elevation 43 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Crescent City 3 Nnw. 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 11 and the first fall freeze around November 23, a growing season of about 256 days.

Median at 36°F
last April 23, first November 1
Median at 32°F
last March 11, first November 23
Median at 28°F
last January 17, first December 17

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 19May 9May 3Apr 29Apr 23Apr 17Apr 11Apr 3Mar 27
32°FApr 12Mar 31Mar 25Mar 18Mar 11Mar 3Feb 25Feb 16Jan 31
28°FMar 7Feb 24Feb 7Jan 29Jan 17Jan 7Dec 31Dec 20Dec 8
24°FJan 22Jan 13Jan 6Jan 1Dec 30Dec 22Dec 17Dec 12Dec 6
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°FOct 10Oct 18Oct 24Oct 29Nov 1Nov 4Nov 9Nov 13Nov 20
32°FNov 1Nov 8Nov 14Nov 18Nov 23Nov 28Dec 2Dec 11Dec 25
28°FNov 18Nov 30Dec 3Dec 10Dec 17Dec 26Jan 3Jan 16Feb 15
24°FDec 1Dec 9Dec 12Dec 18Dec 23Dec 29Jan 1Jan 9Jan 20
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°F225212205197190183176167154
32°F307288276266256247239229216
28°F365365356345336330321306288
24°F365365365365365365365365350
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
99% of years
28°F or colder
75% of years
24°F or colder
18% of years
20°F or colder
4% 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
4,673
Cooling degree days, base 65°F
4
Growing degree days, base 40°F
4,473
Growing degree days, base 45°F
2,770
Growing degree days, base 50°F
1,363
Growing degree days, base 55°F
446
Growing degree days, base 60°F
63

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January553027
February484027
March508034
April434056
May3650111
June2820169
July2100256
August1910274
September2361215
October3492131
November477043
December584019

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 15.7 km from Smith River. 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 USC00042147 (Crescent City 3 Nnw). Public domain.