Mora County climate

Mora County Frost Dates and Growing Season

NOAA 1991-2020 normals for Valmora, 21.6 km from Mora County, elevation 6325 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Valmora. 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 18 and the first fall freeze around October 1, a growing season of about 135 days.

Median at 36°F
last May 31, first September 24
Median at 32°F
last May 18, first October 1
Median at 28°F
last May 5, first October 9

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 12Jun 7Jun 4Jun 1May 31May 28May 25May 22May 17
32°FJun 3May 28May 24May 21May 18May 15May 12May 8May 4
28°FMay 20May 15May 12May 9May 5May 3Apr 30Apr 27Apr 22
24°FMay 9May 4May 1Apr 29Apr 26Apr 22Apr 19Apr 15Apr 10
20°FApr 30Apr 25Apr 20Apr 16Apr 12Apr 9Apr 6Apr 2Mar 29
16°FApr 19Apr 11Apr 6Apr 3Mar 31Mar 27Mar 21Mar 16Mar 9

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 12Sep 17Sep 19Sep 21Sep 24Sep 26Sep 28Oct 1Oct 3
32°FSep 21Sep 24Sep 27Sep 30Oct 1Oct 3Oct 5Oct 8Oct 12
28°FSep 27Oct 1Oct 4Oct 6Oct 9Oct 11Oct 14Oct 18Oct 21
24°FOct 5Oct 10Oct 13Oct 17Oct 19Oct 22Oct 25Oct 29Nov 3
20°FOct 14Oct 19Oct 23Oct 27Oct 30Nov 1Nov 4Nov 7Nov 12
16°FOct 24Oct 29Nov 1Nov 4Nov 6Nov 9Nov 13Nov 17Nov 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°F13112412111811511010710297
32°F153147143139135131127123116
28°F175169163159155151148142135
24°F196190184181177172168163156
20°F219212208204199195190184176
16°F245238231226221217213207199

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
5,683
Cooling degree days, base 65°F
358
Growing degree days, base 40°F
4,652
Growing degree days, base 45°F
3,432
Growing degree days, base 50°F
2,398
Growing degree days, base 55°F
1,553
Growing degree days, base 60°F
870

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,00301
February82902
March73309
April507059
May2716222
June5170470
July6157617
August13105556
September12219349
October4282105
November72309
December99801

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 21.6 km from Mora 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 USC00299330 (Valmora). Public domain.