Anacortes climate

Anacortes Frost Dates and Growing Season

NOAA 1991-2020 normals for Anacortes, 0.1 km from Anacortes, elevation 20 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Anacortes. 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 8 and the first fall freeze around November 20, a growing season of about 255 days.

Median at 36°F
last April 1, first November 2
Median at 32°F
last March 8, first November 20
Median at 28°F
last February 15, first December 5

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°FApr 21Apr 13Apr 7Apr 3Apr 1Mar 30Mar 26Mar 22Mar 15
32°FMar 28Mar 21Mar 16Mar 12Mar 8Mar 4Feb 28Feb 25Feb 17
28°FMar 5Feb 28Feb 24Feb 19Feb 15Feb 8Jan 31Jan 17Jan 5
24°FFeb 21Feb 10Jan 31Jan 22Jan 13Jan 4Dec 31Dec 17Dec 7
20°FFeb 6Jan 27Jan 14Jan 3Dec 31Dec 21Dec 13Dec 6Dec 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 17Oct 22Oct 27Oct 30Nov 2Nov 6Nov 10Nov 15Nov 22
32°FNov 1Nov 6Nov 10Nov 14Nov 20Nov 24Nov 28Dec 2Dec 11
28°FNov 13Nov 21Nov 25Dec 1Dec 5Dec 11Dec 18Dec 28Jan 9
24°FNov 22Nov 30Dec 6Dec 11Dec 17Dec 25Jan 1Jan 10Jan 29
20°FNov 27Dec 3Dec 7Dec 11Dec 19Dec 28Jan 1Jan 15Jan 29
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°F239230224218214209204198189
32°F288276268261255249243237228
28°F345330320311304296287277266
24°F365365361353343335327316306
20°F365365365365365365360345334
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
99% of years
24°F or colder
76% of years
20°F or colder
38% of years
16°F or colder
8% 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
4,520
Cooling degree days, base 65°F
92
Growing degree days, base 40°F
4,812
Growing degree days, base 45°F
3,256
Growing degree days, base 50°F
2,013
Growing degree days, base 55°F
1,089
Growing degree days, base 60°F
435

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January69806
February59803
March558020
April410073
May2562214
June13611326
July5336448
August4534454
September1369323
October3610122
November554021
December71603

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 0.1 km from Anacortes. 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 USC00450176 (Anacortes). Public domain.