Omak climate

Omak Frost Dates and Growing Season

NOAA 1991-2020 normals for Omak AP, 5.6 km from Omak, elevation 1296 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Omak AP. 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 30 and the first fall freeze around October 7, a growing season of about 160 days.

Median at 36°F
last May 13, first September 28
Median at 32°F
last April 30, first October 7
Median at 28°F
last April 14, first October 19

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°FJun 1May 25May 21May 17May 13May 10May 6May 2Apr 28
32°FMay 15May 10May 6May 2Apr 30Apr 27Apr 24Apr 20Apr 14
28°FMay 2Apr 27Apr 23Apr 18Apr 14Apr 10Apr 5Apr 1Mar 26
24°FApr 14Apr 6Apr 1Mar 28Mar 24Mar 18Mar 13Mar 8Mar 4
20°FMar 19Mar 12Mar 7Mar 3Feb 28Feb 26Feb 22Feb 17Feb 10
16°FMar 6Feb 28Feb 25Feb 22Feb 17Feb 13Feb 8Feb 1Jan 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 12Sep 17Sep 22Sep 25Sep 28Oct 1Oct 3Oct 5Oct 11
32°FSep 23Sep 29Oct 1Oct 4Oct 7Oct 10Oct 13Oct 17Oct 22
28°FOct 3Oct 7Oct 11Oct 15Oct 19Oct 22Oct 26Oct 30Nov 4
24°FOct 13Oct 19Oct 23Oct 27Oct 30Nov 2Nov 6Nov 10Nov 18
20°FOct 22Oct 30Nov 3Nov 7Nov 12Nov 16Nov 20Nov 25Dec 2
16°FOct 31Nov 9Nov 15Nov 21Nov 25Nov 30Dec 4Dec 10Dec 19

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°F156150145142136132127122113
32°F183174169164160156152147139
28°F215206199194188183177171163
24°F250241235229222216210202194
20°F287276268262256251245239228
16°F319307299291283276269262252

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
6,177
Cooling degree days, base 65°F
703
Growing degree days, base 40°F
4,857
Growing degree days, base 45°F
3,719
Growing degree days, base 50°F
2,743
Growing degree days, base 55°F
1,917
Growing degree days, base 60°F
1,231

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14500
February91000
March71908
April457174
May21420281
June7881453
July10281736
August11253707
September11766402
October495281
November87201
December1,15000

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 5.6 km from Omak. 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 USW00094197 (Omak AP). Public domain.