Cheyenne County climate

Cheyenne County Frost Dates and Growing Season

NOAA 1991-2020 normals for Kit Carson 9NNE, 12.3 km from Cheyenne County, elevation 4346 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kit Carson 9NNE. 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 7 and the first fall freeze around October 6, a growing season of about 151 days.

Median at 36°F
last May 16, first September 28
Median at 32°F
last May 7, first October 6
Median at 28°F
last April 28, first October 14

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 3May 29May 24May 20May 16May 14May 11May 8May 4
32°FMay 24May 17May 13May 9May 7May 4May 2Apr 29Apr 23
28°FMay 11May 6May 3Apr 30Apr 28Apr 25Apr 20Apr 17Apr 12
24°FMay 1Apr 26Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 2
20°FApr 22Apr 16Apr 12Apr 8Apr 5Apr 3Mar 31Mar 27Mar 21
16°FApr 11Apr 5Apr 2Mar 29Mar 24Mar 20Mar 16Mar 11Mar 6

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 17Sep 22Sep 24Sep 27Sep 28Oct 1Oct 3Oct 5Oct 8
32°FSep 25Sep 29Oct 1Oct 4Oct 6Oct 8Oct 11Oct 13Oct 17
28°FOct 2Oct 6Oct 9Oct 11Oct 14Oct 16Oct 19Oct 21Oct 24
24°FOct 10Oct 15Oct 18Oct 20Oct 23Oct 25Oct 28Nov 1Nov 5
20°FOct 17Oct 22Oct 26Oct 29Nov 1Nov 3Nov 6Nov 10Nov 15
16°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 12Nov 15Nov 19Nov 24

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°F151146141137133129125121114
32°F168162158155151147144139133
28°F188181177173169166162157151
24°F208201196192188184180175168
20°F229222217213208204198193186
16°F248242237232228223218212205

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
6,081
Cooling degree days, base 65°F
887
Growing degree days, base 40°F
5,250
Growing degree days, base 45°F
4,098
Growing degree days, base 50°F
3,091
Growing degree days, base 55°F
2,224
Growing degree days, base 60°F
1,489

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,13000
February95301
March764023
April497183
May22732296
June35175590
July3328790
August7256714
September9791450
October4455132
November806011
December1,11700

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 12.3 km from Cheyenne 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 USC00054606 (Kit Carson 9NNE). Public domain.