Rio Blanco County climate

Rio Blanco County Frost Dates and Growing Season

NOAA 1991-2020 normals for Meeker, 27.2 km from Rio Blanco County, elevation 6229 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Meeker. 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 June 4 and the first fall freeze around September 16, a growing season of about 104 days.

Median at 32°F
last June 4, first September 16
Median at 28°F
last May 21, first September 27

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°FJun 23Jun 16Jun 11Jun 7Jun 4Jun 1May 29May 25May 21
28°FJun 7Jun 1May 28May 24May 21May 18May 14May 9May 4
24°FMay 23May 18May 14May 9May 6May 3Apr 30Apr 27Apr 21
20°FMay 12May 5May 1Apr 28Apr 25Apr 21Apr 16Apr 11Apr 4
16°FApr 28Apr 23Apr 18Apr 13Apr 8Apr 3Mar 31Mar 25Mar 17

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°FSep 3Sep 7Sep 11Sep 14Sep 16Sep 19Sep 22Sep 26Oct 1
28°FSep 11Sep 17Sep 20Sep 24Sep 27Sep 30Oct 3Oct 6Oct 11
24°FSep 22Sep 27Oct 2Oct 5Oct 8Oct 12Oct 15Oct 19Oct 23
20°FOct 4Oct 11Oct 14Oct 18Oct 21Oct 23Oct 26Oct 29Nov 2
16°FOct 14Oct 20Oct 23Oct 26Oct 28Nov 1Nov 3Nov 5Nov 10

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°F978983797570635748
32°F12511711310810499958979
28°F150142137132128123118112103
24°F176168162157153148143137128
20°F203194189183178173168162154
16°F228220212206202197191185176

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
7,887
Cooling degree days, base 65°F
171
Growing degree days, base 40°F
3,519
Growing degree days, base 45°F
2,523
Growing degree days, base 50°F
1,696
Growing degree days, base 55°F
1,023
Growing degree days, base 60°F
506

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,39000
February1,09200
March89903
April664019
May4281115
June16620312
July2890527
August6055460
September2505225
October620034
November95101
December1,34100

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 27.2 km from Rio Blanco 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 USC00055484 (Meeker). Public domain.