Pend Oreille County climate

Pend Oreille County Frost Dates and Growing Season

NOAA 1991-2020 normals for Priest Rvr Exp Stn, 38.1 km from Pend Oreille County, elevation 2371 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Priest Rvr Exp Stn. 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 May 20 and the first fall freeze around September 13, a growing season of about 114 days.

Median at 32°F
last May 20, first September 13
Median at 28°F
last May 4, first September 28

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°F–––––––––
32°FJun 4May 30May 27May 24May 20May 17May 14May 11May 6
28°FMay 17May 13May 10May 7May 4Apr 30Apr 29Apr 25Apr 19
24°FMay 3Apr 27Apr 23Apr 18Apr 13Apr 9Apr 4Mar 31Mar 26
20°FApr 13Apr 4Mar 31Mar 27Mar 22Mar 18Mar 14Mar 10Mar 5
16°FMar 23Mar 18Mar 14Mar 10Mar 8Mar 5Mar 2Feb 28Feb 21

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°F–––––––––
32°FSep 1Sep 3Sep 7Sep 9Sep 13Sep 16Sep 19Sep 23Sep 30
28°FSep 12Sep 17Sep 21Sep 25Sep 28Oct 1Oct 3Oct 7Oct 13
24°FSep 26Oct 1Oct 4Oct 7Oct 10Oct 15Oct 19Oct 25Nov 1
20°FOct 6Oct 13Oct 20Oct 25Oct 29Nov 2Nov 7Nov 14Nov 21
16°FOct 21Oct 29Nov 4Nov 9Nov 14Nov 18Nov 24Nov 30Dec 8

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°F999085797468625545
32°F1371291251191141101059992
28°F168160155150146142138133125
24°F208199191186180175169164154
20°F247239232226220213207200189
16°F278269261254249245239231220

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
7,538
Cooling degree days, base 65°F
157
Growing degree days, base 40°F
3,307
Growing degree days, base 45°F
2,354
Growing degree days, base 50°F
1,559
Growing degree days, base 55°F
913
Growing degree days, base 60°F
442

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18000
February99700
March89100
April632017
May3632145
June19915270
July6477477
August7959445
September2925187
October680017
November96800
December1,19300

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 38.1 km from Pend Oreille County. 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 USC00107386 (Priest Rvr Exp Stn). Public domain.