Greeley County climate

Greeley County Frost Dates and Growing Season

NOAA 1991-2020 normals for Tribune 1W, 3.3 km from Greeley County, elevation 3634 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tribune 1W. 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 2 and the first fall freeze around October 11, a growing season of about 160 days.

Median at 36°F
last May 12, first October 3
Median at 32°F
last May 2, first October 11
Median at 28°F
last April 23, first October 19

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 25May 21May 17May 14May 12May 9May 7May 4May 1
32°FMay 16May 11May 8May 5May 2Apr 30Apr 29Apr 25Apr 20
28°FMay 7May 1Apr 29Apr 27Apr 23Apr 20Apr 17Apr 14Apr 10
24°FApr 28Apr 23Apr 20Apr 17Apr 14Apr 11Apr 7Apr 4Mar 31
20°FApr 19Apr 15Apr 10Apr 6Apr 3Mar 31Mar 28Mar 23Mar 16
16°FApr 10Apr 3Mar 31Mar 26Mar 21Mar 17Mar 13Mar 8Mar 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 22Sep 26Sep 28Oct 1Oct 3Oct 4Oct 6Oct 9Oct 13
32°FSep 30Oct 3Oct 5Oct 8Oct 11Oct 13Oct 15Oct 17Oct 20
28°FOct 6Oct 11Oct 14Oct 17Oct 19Oct 21Oct 23Oct 26Oct 30
24°FOct 13Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 3Nov 9
20°FOct 19Oct 24Oct 28Oct 31Nov 3Nov 6Nov 10Nov 14Nov 18
16°FOct 26Nov 1Nov 5Nov 9Nov 13Nov 16Nov 19Nov 22Nov 27

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°F158153149145142139135130124
32°F175170166163160156152148142
28°F193188184180176173169164159
24°F214207202198195190186180174
20°F234227221216212208204198190
16°F257249242238233227222216208

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
5,679
Cooling degree days, base 65°F
1,051
Growing degree days, base 40°F
5,668
Growing degree days, base 45°F
4,456
Growing degree days, base 50°F
3,391
Growing degree days, base 55°F
2,475
Growing degree days, base 60°F
1,696

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08001
February89704
March723036
April4613115
May19550339
June27219642
July3361823
August7286744
September88121489
October39710170
November746028
December1,05401

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 3.3 km from Greeley County. 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 USC00148235 (Tribune 1W). Public domain.