Wright climate

Wright Frost Dates and Growing Season

NOAA 1991-2020 normals for Wright 12W, 19.4 km from Wright, elevation 5020 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wright 12W. 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 25 and the first fall freeze around September 23, a growing season of about 120 days.

Median at 36°F
last June 5, first September 12
Median at 32°F
last May 25, first September 23
Median at 28°F
last May 13, first October 2

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 21Jun 17Jun 12Jun 8Jun 5Jun 3May 31May 28May 24
32°FJun 8Jun 3May 31May 28May 25May 23May 20May 17May 14
28°FMay 26May 21May 18May 15May 13May 10May 7May 5May 1
24°FMay 13May 9May 6May 3May 1Apr 29Apr 26Apr 22Apr 16
20°FMay 3Apr 29Apr 26Apr 23Apr 19Apr 16Apr 13Apr 9Apr 5
16°FApr 25Apr 20Apr 15Apr 12Apr 8Apr 5Apr 3Mar 31Mar 24

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°FAug 29Sep 3Sep 6Sep 9Sep 12Sep 15Sep 18Sep 22Sep 26
32°FSep 8Sep 14Sep 17Sep 21Sep 23Sep 26Sep 28Oct 1Oct 5
28°FSep 18Sep 24Sep 27Sep 30Oct 2Oct 5Oct 8Oct 12Oct 17
24°FSep 27Oct 2Oct 5Oct 8Oct 12Oct 15Oct 18Oct 21Oct 25
20°FOct 5Oct 10Oct 14Oct 17Oct 20Oct 22Oct 26Oct 29Nov 2
16°FOct 12Oct 17Oct 20Oct 24Oct 27Oct 30Nov 3Nov 6Nov 11

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°F1171111061029893898476
32°F13813212812412011611110598
28°F158153148145141137133128121
24°F181174170166162158154149143
20°F202195190186182178173168162
16°F222214208204199194191185179

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
7,839
Cooling degree days, base 65°F
426
Growing degree days, base 40°F
3,885
Growing degree days, base 45°F
2,904
Growing degree days, base 50°F
2,074
Growing degree days, base 55°F
1,389
Growing degree days, base 60°F
837

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,27600
February1,11801
March95007
April708028
May4424131
June15848351
July30182617
August45154576
September23237291
October637163
November96909
December1,27500

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 19.4 km from Wright. 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 USC00489805 (Wright 12W). Public domain.