Payette climate

Payette Frost Dates and Growing Season

NOAA 1991-2020 normals for Payette, 0.3 km from Payette, elevation 2150 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Payette. 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 19 and the first fall freeze around October 20, a growing season of about 183 days.

Median at 36°F
last May 2, first October 8
Median at 32°F
last April 19, first October 20
Median at 28°F
last March 31, first October 31

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 21May 13May 9May 5May 2Apr 30Apr 28Apr 23Apr 18
32°FMay 5Apr 30Apr 27Apr 23Apr 19Apr 16Apr 11Apr 7Apr 1
28°FApr 20Apr 13Apr 8Apr 3Mar 31Mar 28Mar 21Mar 14Mar 7
24°FApr 2Mar 26Mar 18Mar 11Mar 7Mar 4Feb 28Feb 22Feb 16
20°FMar 10Mar 3Feb 27Feb 22Feb 18Feb 14Feb 10Feb 4Jan 26
16°FFeb 28Feb 21Feb 15Feb 8Feb 3Jan 29Jan 21Jan 11Jan 1

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 25Sep 30Oct 4Oct 6Oct 8Oct 11Oct 14Oct 17Oct 22
32°FOct 6Oct 10Oct 14Oct 17Oct 20Oct 23Oct 25Oct 29Nov 4
28°FOct 17Oct 22Oct 26Oct 29Oct 31Nov 2Nov 6Nov 11Nov 16
24°FOct 26Oct 31Nov 4Nov 9Nov 13Nov 16Nov 21Nov 24Nov 29
20°FNov 4Nov 11Nov 16Nov 21Nov 25Nov 28Dec 2Dec 7Dec 15
16°FNov 14Nov 22Nov 27Dec 1Dec 5Dec 11Dec 17Dec 23Jan 3

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°F176170164161158154150144135
32°F206198192188183179174169161
28°F238231224218214208203196189
24°F274265258251246241235226218
20°F309298290284278271265258247
16°F343332324316308300293284272

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
98% 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
5,203
Cooling degree days, base 65°F
925
Growing degree days, base 40°F
5,585
Growing degree days, base 45°F
4,306
Growing degree days, base 50°F
3,204
Growing degree days, base 55°F
2,284
Growing degree days, base 60°F
1,525

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03700
February76402
March588028
April3882111
May17040341
June53134531
July3358820
August8304761
September7783457
October3755143
November72309
December1,01701

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 0.3 km from Payette. 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 USC00106891 (Payette). Public domain.