Wells climate

Wells Frost Dates and Growing Season

NOAA 1991-2020 normals for Wells, 1.5 km from Wells, elevation 5700 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wells. 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 10 and the first fall freeze around September 16, a growing season of about 94 days.

Median at 32°F
last June 10, first September 16
Median at 28°F
last May 23, first September 26

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 26Jun 21Jun 17Jun 13Jun 10Jun 7Jun 3May 31May 24
28°FJun 12Jun 5May 31May 27May 23May 18May 15May 10May 4
24°FMay 27May 16May 13May 9May 6May 3Apr 30Apr 26Apr 20
20°FMay 10May 4Apr 30Apr 26Apr 21Apr 18Apr 14Apr 9Mar 31
16°FApr 24Apr 17Apr 12Apr 6Apr 3Mar 30Mar 24Mar 16Mar 7

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 1Sep 6Sep 9Sep 13Sep 16Sep 19Sep 21Sep 24Oct 1
28°FSep 10Sep 16Sep 20Sep 23Sep 26Sep 29Oct 2Oct 6Oct 10
24°FSep 22Sep 27Sep 30Oct 4Oct 7Oct 10Oct 13Oct 16Oct 21
20°FSep 30Oct 5Oct 10Oct 13Oct 16Oct 19Oct 23Oct 26Nov 1
16°FOct 9Oct 14Oct 18Oct 23Oct 26Oct 30Nov 3Nov 7Nov 14

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°F908480757167625747
32°F117109104999490868173
28°F14814013412912411911410799
24°F173166161156152147141136125
20°F201192185180176171166160153
16°F239228220213206200194187178

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
7,623
Cooling degree days, base 65°F
279
Growing degree days, base 40°F
3,580
Growing degree days, base 45°F
2,603
Growing degree days, base 50°F
1,801
Growing degree days, base 55°F
1,142
Growing degree days, base 60°F
634

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,27600
February1,03000
March88001
April675017
May4371115
June19224295
July27147584
August4699518
September2409235
October625034
November94502
December1,25100

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 1.5 km from Wells. 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 USC00268988 (Wells). Public domain.