Wenatchee climate

Wenatchee Frost Dates and Growing Season

NOAA 1991-2020 normals for Wenatchee, 0.5 km from Wenatchee, elevation 626 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wenatchee. 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 4 and the first fall freeze around October 28, a growing season of about 208 days.

Median at 36°F
last April 21, first October 17
Median at 32°F
last April 4, first October 28
Median at 28°F
last March 13, first November 10

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 5Apr 30Apr 27Apr 24Apr 21Apr 18Apr 15Apr 12Apr 7
32°FApr 19Apr 14Apr 10Apr 7Apr 4Apr 1Mar 30Mar 25Mar 17
28°FApr 2Mar 27Mar 21Mar 17Mar 13Mar 11Mar 7Mar 4Mar 1
24°FMar 13Mar 8Mar 4Mar 2Feb 28Feb 25Feb 21Feb 16Feb 8
20°FMar 3Feb 27Feb 22Feb 17Feb 12Feb 7Feb 2Jan 23Jan 11
16°FFeb 25Feb 16Feb 9Feb 3Jan 29Jan 21Jan 13Jan 5Dec 28

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 6Oct 10Oct 12Oct 15Oct 17Oct 20Oct 22Oct 25Oct 29
32°FOct 17Oct 20Oct 23Oct 26Oct 28Oct 31Nov 2Nov 6Nov 11
28°FOct 26Oct 31Nov 3Nov 6Nov 10Nov 14Nov 17Nov 21Nov 25
24°FNov 4Nov 10Nov 14Nov 19Nov 23Nov 26Nov 30Dec 4Dec 12
20°FNov 16Nov 24Nov 28Dec 1Dec 6Dec 11Dec 18Dec 26Jan 5
16°FNov 27Dec 3Dec 9Dec 16Dec 21Dec 27Jan 1Jan 10Jan 25

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°F196190186182179174170166160
32°F229222217213208204199195188
28°F261254248244239235230224217
24°F299288281275270265260254245
20°F334323316308302296288280270
16°F364353343335330324317308295

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
98% of years
16°F or colder
88% 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
5,410
Cooling degree days, base 65°F
889
Growing degree days, base 40°F
5,433
Growing degree days, base 45°F
4,210
Growing degree days, base 50°F
3,152
Growing degree days, base 55°F
2,251
Growing degree days, base 60°F
1,493

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,06300
February81900
March656012
April3872106
May15842351
June40121531
July3330792
August5304764
September7087467
October3973126
November76604
December1,04500

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 0.5 km from Wenatchee. 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 USC00459074 (Wenatchee). Public domain.