Priest River climate

Priest River Frost Dates and Growing Season

NOAA 1991-2020 normals for Newport, 10.1 km from Priest River, elevation 2162 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Newport. 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 12 and the first fall freeze around September 21, a growing season of about 130 days.

Median at 36°F
last June 1, first September 6
Median at 32°F
last May 12, first September 21
Median at 28°F
last April 30, first October 2

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 26Jun 16Jun 10Jun 5Jun 1May 29May 25May 19May 14
32°FMay 29May 23May 18May 14May 12May 9May 6May 3Apr 28
28°FMay 14May 9May 6May 3Apr 30Apr 27Apr 23Apr 19Apr 13
24°FMay 2Apr 26Apr 20Apr 16Apr 10Apr 5Mar 31Mar 28Mar 19
20°FApr 9Apr 1Mar 29Mar 24Mar 19Mar 15Mar 10Mar 5Feb 28
16°FMar 21Mar 15Mar 10Mar 7Mar 4Mar 1Feb 26Feb 20Feb 10

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°FAug 24Aug 30Sep 1Sep 4Sep 6Sep 9Sep 12Sep 16Sep 21
32°FSep 5Sep 10Sep 15Sep 18Sep 21Sep 24Sep 27Oct 1Oct 5
28°FSep 18Sep 23Sep 27Sep 30Oct 2Oct 5Oct 10Oct 18Oct 26
24°FSep 30Oct 4Oct 8Oct 15Oct 22Oct 27Nov 1Nov 6Nov 14
20°FOct 7Oct 19Oct 27Nov 2Nov 6Nov 11Nov 16Nov 22Nov 29
16°FOct 21Nov 2Nov 9Nov 14Nov 19Nov 24Nov 29Dec 5Dec 16

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°F1181111051009590847868
32°F151145139135130126121115107
28°F185175168162157152148142135
24°F227216209201195188182174164
20°F262252244239233227220213201
16°F293282274266259251245237226

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
7,078
Cooling degree days, base 65°F
256
Growing degree days, base 40°F
3,687
Growing degree days, base 45°F
2,672
Growing degree days, base 50°F
1,824
Growing degree days, base 55°F
1,132
Growing degree days, base 60°F
602

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14900
February95800
March83901
April590028
May3274175
June16728314
July44117538
August6195499
September24312234
October619034
November92300
December1,16100

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 10.1 km from Priest River. 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 USC00455844 (Newport). Public domain.