Valle climate

Valle Frost Dates and Growing Season

NOAA 1991-2020 normals for Williams 35 Nnw, 21.2 km from Valle, elevation 5990 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Williams 35 Nnw. 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 9 and the first fall freeze around October 19, a growing season of about 161 days.

Median at 36°F
last May 24, first October 6
Median at 32°F
last May 9, first October 19
Median at 28°F
last April 24, first October 31

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 6Jun 2May 31May 28May 24May 20May 17May 14May 8
32°FMay 27May 21May 15May 12May 9May 5May 2Apr 29Apr 24
28°FMay 14May 6May 1Apr 28Apr 24Apr 21Apr 17Apr 12Apr 6
24°FApr 27Apr 20Apr 15Apr 11Apr 7Apr 4Mar 31Mar 23Mar 16
20°FApr 11Apr 3Mar 30Mar 23Mar 17Mar 11Mar 6Mar 1Feb 21
16°FMar 24Mar 12Mar 5Feb 28Feb 24Feb 18Feb 12Feb 5Jan 28

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 24Sep 28Oct 1Oct 4Oct 6Oct 9Oct 12Oct 16Oct 20
32°FOct 3Oct 8Oct 11Oct 15Oct 19Oct 21Oct 24Oct 28Nov 3
28°FOct 14Oct 20Oct 24Oct 27Oct 31Nov 3Nov 5Nov 9Nov 13
24°FOct 23Oct 30Nov 3Nov 5Nov 9Nov 13Nov 15Nov 19Nov 24
20°FNov 1Nov 7Nov 12Nov 16Nov 19Nov 22Nov 26Nov 30Dec 5
16°FNov 13Nov 19Nov 23Nov 26Nov 29Dec 2Dec 6Dec 12Dec 18

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°F157151144140136131127121114
32°F183176171166161157152145137
28°F211202197193188183178172162
24°F240232226220215209203197188
20°F276267260251245239231223214
16°F308297290283276271264255244

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
5,334
Cooling degree days, base 65°F
567
Growing degree days, base 40°F
5,070
Growing degree days, base 45°F
3,811
Growing degree days, base 50°F
2,748
Growing degree days, base 55°F
1,866
Growing degree days, base 60°F
1,138

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January96300
February79201
March674012
April485063
May26113242
June40106516
July1230694
August6173632
September7944417
October3641151
November678020
December99200

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 21.2 km from Valle. 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 USW00053155 (Williams 35 Nnw). Public domain.