Crook County climate

Crook County Frost Dates and Growing Season

NOAA 1991-2020 normals for Hulett, 11.1 km from Crook County, elevation 3758 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hulett. 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 17 and the first fall freeze around September 23, a growing season of about 128 days.

Median at 36°F
last May 29, first September 12
Median at 32°F
last May 17, first September 23
Median at 28°F
last May 6, first October 3

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 14Jun 8Jun 4May 31May 29May 27May 24May 21May 17
32°FMay 30May 25May 22May 19May 17May 14May 11May 9May 6
28°FMay 20May 15May 11May 9May 6May 4May 2Apr 30Apr 24
24°FMay 9May 4May 1Apr 28Apr 26Apr 23Apr 20Apr 16Apr 10
20°FApr 29Apr 24Apr 20Apr 16Apr 13Apr 9Apr 6Apr 2Mar 29
16°FApr 17Apr 13Apr 9Apr 4Apr 2Mar 31Mar 26Mar 19Mar 12

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 29Sep 2Sep 6Sep 9Sep 12Sep 15Sep 18Sep 22Sep 27
32°FSep 8Sep 13Sep 17Sep 20Sep 23Sep 27Sep 30Oct 2Oct 7
28°FSep 17Sep 24Sep 28Oct 1Oct 3Oct 6Oct 8Oct 13Oct 17
24°FSep 28Oct 2Oct 6Oct 10Oct 14Oct 17Oct 20Oct 23Oct 27
20°FOct 7Oct 14Oct 17Oct 21Oct 23Oct 26Oct 29Nov 1Nov 6
16°FOct 18Oct 23Oct 26Oct 29Nov 1Nov 4Nov 8Nov 12Nov 17

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°F124118113109105101979286
32°F146140136131128124120115109
28°F167160156153149145141136129
24°F190183178174170167161156149
20°F215207202198193188184179171
16°F238229223218212208204199191

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
7,734
Cooling degree days, base 65°F
486
Growing degree days, base 40°F
4,031
Growing degree days, base 45°F
3,032
Growing degree days, base 50°F
2,189
Growing degree days, base 55°F
1,484
Growing degree days, base 60°F
915

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,32100
February1,13100
March94608
April675031
May38710166
June12366398
July27203642
August45167589
September22938289
October609162
November96305
December1,28000

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 11.1 km from Crook County. 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 USC00484760 (Hulett). Public domain.