Wright County climate

Wright County Frost Dates and Growing Season

NOAA 1991-2020 normals for Clarion, 1.5 km from Wright County, elevation 1156 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clarion. 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 April 30 and the first fall freeze around October 10, a growing season of about 162 days.

Median at 36°F
last May 8, first October 1
Median at 32°F
last April 30, first October 10
Median at 28°F
last April 19, first October 19

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°FMay 21May 16May 12May 10May 8May 5May 3May 1Apr 27
32°FMay 12May 8May 4May 2Apr 30Apr 27Apr 23Apr 20Apr 17
28°FMay 3Apr 29Apr 25Apr 22Apr 19Apr 16Apr 14Apr 10Apr 4
24°FApr 26Apr 20Apr 16Apr 12Apr 10Apr 7Apr 4Apr 1Mar 24
20°FApr 17Apr 10Apr 7Apr 4Apr 1Mar 28Mar 23Mar 19Mar 13
16°FApr 7Apr 1Mar 28Mar 24Mar 20Mar 16Mar 13Mar 9Mar 4

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 17Sep 22Sep 25Sep 28Oct 1Oct 3Oct 5Oct 8Oct 12
32°FSep 27Oct 1Oct 4Oct 7Oct 10Oct 12Oct 15Oct 18Oct 21
28°FOct 4Oct 10Oct 14Oct 17Oct 19Oct 22Oct 24Oct 27Oct 31
24°FOct 16Oct 21Oct 24Oct 26Oct 29Nov 1Nov 2Nov 6Nov 10
20°FOct 25Oct 31Nov 2Nov 4Nov 6Nov 9Nov 11Nov 15Nov 20
16°FNov 3Nov 6Nov 9Nov 12Nov 14Nov 17Nov 19Nov 23Nov 29

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°F160154150146143139136132125
32°F179174170166162159154149142
28°F201194189186181177173169162
24°F220214209205201197193188181
20°F240233227223219215211207199
16°F259251246242237232228223215

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
7,309
Cooling degree days, base 65°F
804
Growing degree days, base 40°F
4,989
Growing degree days, base 45°F
3,925
Growing degree days, base 50°F
2,971
Growing degree days, base 55°F
2,130
Growing degree days, base 60°F
1,404

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51900
February1,22801
March954015
April545581
May21650319
June27185609
July6268727
August14203654
September12583415
October45410136
November897014
December1,32700

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 Wright 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 USC00131541 (Clarion). Public domain.