Cook climate

Cook Frost Dates and Growing Season

NOAA 1991-2020 normals for Cook 8NE, 12.6 km from Cook, elevation 1355 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cook 8NE. 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 October 1, a growing season of about 138 days.

Median at 36°F
last May 26, first September 21
Median at 32°F
last May 12, first October 1
Median at 28°F
last May 3, first October 11

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 10Jun 4Jun 1May 29May 26May 24May 20May 16May 11
32°FMay 29May 24May 19May 15May 12May 10May 7May 4May 1
28°FMay 16May 11May 8May 5May 3May 1Apr 29Apr 26Apr 21
24°FMay 7May 2Apr 30Apr 28Apr 26Apr 23Apr 20Apr 17Apr 11
20°FApr 28Apr 25Apr 22Apr 19Apr 17Apr 14Apr 12Apr 8Apr 4
16°FApr 23Apr 19Apr 15Apr 12Apr 10Apr 7Apr 5Apr 2Mar 30

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 8Sep 12Sep 15Sep 18Sep 21Sep 24Sep 27Sep 30Oct 3
32°FSep 17Sep 22Sep 25Sep 28Oct 1Oct 3Oct 5Oct 9Oct 13
28°FSep 27Oct 1Oct 4Oct 8Oct 11Oct 14Oct 18Oct 22Oct 28
24°FOct 9Oct 13Oct 17Oct 21Oct 25Oct 29Nov 1Nov 4Nov 7
20°FOct 21Oct 26Oct 31Nov 1Nov 4Nov 6Nov 8Nov 12Nov 16
16°FOct 31Nov 3Nov 5Nov 8Nov 10Nov 13Nov 16Nov 19Nov 23

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°F13612912412011711210810495
32°F159151147142138134130125118
28°F178172168163159155151146139
24°F200194189185181177173168159
20°F219212207203199195191187180
16°F231225220217214210206202195

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
10,016
Cooling degree days, base 65°F
218
Growing degree days, base 40°F
3,321
Growing degree days, base 45°F
2,452
Growing degree days, base 50°F
1,695
Growing degree days, base 55°F
1,059
Growing degree days, base 60°F
558

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,85400
February1,55400
March1,30702
April834013
May4236135
June13938353
July5294507
August7965451
September30215202
October713031
November1,13601
December1,62400

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 12.6 km from Cook. 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 USC00211771 (Cook 8NE). Public domain.