Cheney climate

Cheney Frost Dates and Growing Season

NOAA 1991-2020 normals for Spokane 17 Ssw, 8.6 km from Cheney, elevation 2267 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Spokane 17 Ssw. 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 30 and the first fall freeze around September 4, a growing season of about 94 days.

Median at 32°F
last May 30, first September 4
Median at 28°F
last May 5, first September 15

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°FJul 13Jun 23Jun 13Jun 4May 30May 26May 21May 16May 9
28°FMay 22May 16May 12May 8May 5May 2Apr 29Apr 24Apr 18
24°FMay 5Apr 30Apr 26Apr 20Apr 13Apr 6Mar 31Mar 25Mar 16
20°FApr 19Apr 5Mar 29Mar 22Mar 16Mar 12Mar 8Mar 4Feb 27
16°FMar 23Mar 13Mar 9Mar 5Mar 2Feb 28Feb 24Feb 18Feb 11

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°FAug 21Aug 26Aug 30Sep 1Sep 4Sep 6Sep 9Sep 13Sep 19
28°FSep 2Sep 6Sep 9Sep 12Sep 15Sep 18Sep 22Sep 26Oct 3
24°FSep 12Sep 18Sep 22Sep 27Oct 1Oct 3Oct 7Oct 14Oct 22
20°FSep 28Oct 3Oct 6Oct 12Oct 17Oct 22Oct 28Nov 2Nov 10
16°FOct 10Oct 18Oct 22Oct 28Nov 1Nov 5Nov 12Nov 22Dec 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°F736557514439353125
32°F1201111051009487797056
28°F157148141137131127123118107
24°F204191182176169163155148139
20°F244233224218212206198190176
16°F279267258250243236229222213

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
7,399
Cooling degree days, base 65°F
125
Growing degree days, base 40°F
3,230
Growing degree days, base 45°F
2,224
Growing degree days, base 50°F
1,420
Growing degree days, base 55°F
800
Growing degree days, base 60°F
371

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12100
February95300
March83401
April621018
May4011115
June2429224
July8264446
August9547418
September3145170
October659028
November93301
December1,14500

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 8.6 km from Cheney. 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 USW00004136 (Spokane 17 Ssw). Public domain.