Wells County climate

Wells County Frost Dates and Growing Season

NOAA 1991-2020 normals for Fessenden, 7 km from Wells County, elevation 1620 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fessenden. 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 13 and the first fall freeze around September 28, a growing season of about 139 days.

Median at 36°F
last May 22, first September 20
Median at 32°F
last May 13, first September 28
Median at 28°F
last May 2, first October 6

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 2May 30May 27May 24May 22May 20May 17May 14May 10
32°FMay 26May 21May 18May 15May 13May 10May 7May 4Apr 30
28°FMay 17May 12May 8May 5May 2Apr 30Apr 28Apr 24Apr 19
24°FMay 7May 3Apr 30Apr 27Apr 24Apr 21Apr 17Apr 14Apr 9
20°FApr 30Apr 25Apr 20Apr 17Apr 15Apr 12Apr 8Apr 5Apr 1
16°FApr 21Apr 16Apr 12Apr 9Apr 6Apr 3Apr 1Mar 29Mar 21

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 6Sep 11Sep 14Sep 17Sep 20Sep 22Sep 24Sep 27Oct 1
32°FSep 15Sep 20Sep 23Sep 25Sep 28Sep 30Oct 3Oct 6Oct 11
28°FSep 24Sep 28Oct 1Oct 4Oct 6Oct 9Oct 12Oct 16Oct 21
24°FOct 3Oct 8Oct 12Oct 14Oct 17Oct 20Oct 23Oct 26Oct 31
20°FOct 13Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1Nov 4Nov 9
16°FOct 22Oct 26Oct 30Nov 1Nov 3Nov 5Nov 8Nov 12Nov 17

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°F139133128125121117113109103
32°F155150146142139135131126119
28°F175168163160156153149145138
24°F194187182177174170166161156
20°F212206202198193189184179173
16°F231224219215211208204199192

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
9,098
Cooling degree days, base 65°F
364
Growing degree days, base 40°F
3,851
Growing degree days, base 45°F
2,918
Growing degree days, base 50°F
2,093
Growing degree days, base 55°F
1,378
Growing degree days, base 60°F
795

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,70500
February1,41500
March1,19801
April709032
May34513192
June9964417
July29136572
August45117538
September21932281
October648157
November1,12802
December1,55900

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 7 km from Wells 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 USC00322949 (Fessenden). Public domain.