Montesano climate

Montesano Frost Dates and Growing Season

NOAA 1991-2020 normals for Aberdeen, 17.2 km from Montesano, elevation 10 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Aberdeen. 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 29 and the first fall freeze around November 15, a growing season of about 234 days.

Median at 36°F
last April 23, first October 27
Median at 32°F
last March 29, first November 15
Median at 28°F
last February 18, first December 6

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 11May 5Apr 30Apr 27Apr 23Apr 19Apr 15Apr 10Apr 4
32°FApr 20Apr 12Apr 5Apr 1Mar 29Mar 23Mar 15Mar 6Feb 25
28°FMar 20Mar 7Feb 28Feb 24Feb 18Feb 10Jan 31Jan 16Dec 27
24°FFeb 20Feb 10Jan 29Jan 14Jan 5Dec 29Dec 20Dec 11Dec 2
20°FJan 14Jan 1Dec 31Dec 23Dec 20Dec 16Dec 11Dec 7Dec 1
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 11Oct 17Oct 21Oct 24Oct 27Oct 30Nov 2Nov 7Nov 14
32°FOct 27Nov 1Nov 6Nov 11Nov 15Nov 21Nov 26Dec 1Dec 10
28°FNov 11Nov 21Nov 27Dec 1Dec 6Dec 13Dec 23Jan 2Jan 26
24°FNov 26Dec 1Dec 7Dec 13Dec 19Dec 27Jan 4Jan 16Feb 8
20°FDec 1Dec 5Dec 9Dec 12Dec 17Dec 20Dec 28Jan 1Jan 10
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°F214204198192187182177170163
32°F272258249242234227220213204
28°F351334323311304294284272256
24°F365365365365361351338329314
20°F365365365365365365365365353
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
95% of years
24°F or colder
54% of years
20°F or colder
12% of years
16°F or colder
1% 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
5,017
Cooling degree days, base 65°F
53
Growing degree days, base 40°F
4,271
Growing degree days, base 45°F
2,755
Growing degree days, base 50°F
1,591
Growing degree days, base 55°F
757
Growing degree days, base 60°F
233

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January69603
February60205
March594017
April485140
May3454140
June2187239
July13113347
August11315367
September16512297
October3761116
November572017
December72103

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 17.2 km from Montesano. 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 USC00450008 (Aberdeen). Public domain.