Kamiah climate

Kamiah Frost Dates and Growing Season

NOAA 1991-2020 normals for Kamiah, 0.5 km from Kamiah, elevation 1210 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kamiah. 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 29 and the first fall freeze around October 5, a growing season of about 163 days.

Median at 36°F
last May 11, first September 25
Median at 32°F
last April 29, first October 5
Median at 28°F
last April 7, first October 20

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 31May 24May 18May 14May 11May 8May 5May 2Apr 29
32°FMay 12May 7May 3May 1Apr 29Apr 26Apr 21Apr 17Apr 9
28°FApr 29Apr 22Apr 16Apr 12Apr 7Apr 3Mar 30Mar 25Mar 19
24°FApr 8Mar 31Mar 25Mar 19Mar 14Mar 10Mar 5Feb 28Feb 20
20°FMar 18Mar 11Mar 6Mar 1Feb 26Feb 20Feb 14Feb 6Jan 28
16°FMar 5Feb 28Feb 21Feb 12Feb 6Feb 1Jan 22Jan 13Jan 4

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 5Sep 13Sep 18Sep 22Sep 25Sep 28Oct 1Oct 3Oct 9
32°FSep 22Sep 27Sep 30Oct 3Oct 5Oct 9Oct 13Oct 17Oct 24
28°FOct 1Oct 6Oct 11Oct 16Oct 20Oct 24Oct 29Nov 3Nov 10
24°FOct 15Oct 22Oct 29Nov 2Nov 6Nov 10Nov 15Nov 21Nov 28
20°FOct 28Nov 4Nov 10Nov 15Nov 21Nov 27Dec 1Dec 7Dec 14
16°FNov 5Nov 14Nov 22Nov 28Dec 4Dec 8Dec 15Dec 21Jan 1

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°F156149143139134129123116106
32°F186178172167163158154149139
28°F224213207202196190184177168
24°F267258249241236230223216203
20°F307293284276270264256245233
16°F340326316308300292283273262

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
99% 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
5,662
Cooling degree days, base 65°F
549
Growing degree days, base 40°F
4,802
Growing degree days, base 45°F
3,598
Growing degree days, base 50°F
2,589
Growing degree days, base 55°F
1,749
Growing degree days, base 60°F
1,063

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02500
February75101
March656010
April446179
May21515274
June8062433
July12209662
August10209663
September12352382
October477183
November81303
December1,05400

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 Kamiah. 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 USC00104793 (Kamiah). Public domain.