Adrian climate

Adrian Frost Dates and Growing Season

NOAA 1991-2020 normals for Worthington 2 Nne, 28.4 km from Adrian, elevation 1570 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Worthington 2 Nne. 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 3 and the first fall freeze around October 4, a growing season of about 153 days.

Median at 36°F
last May 12, first September 25
Median at 32°F
last May 3, first October 4
Median at 28°F
last April 23, first October 15

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 25May 20May 17May 15May 12May 10May 7May 4Apr 30
32°FMay 15May 11May 8May 5May 3May 1Apr 28Apr 24Apr 19
28°FMay 6May 2Apr 30Apr 27Apr 23Apr 20Apr 17Apr 13Apr 8
24°FApr 29Apr 23Apr 20Apr 17Apr 14Apr 11Apr 7Apr 5Apr 1
20°FApr 21Apr 15Apr 12Apr 9Apr 6Apr 3Apr 1Mar 27Mar 21
16°FApr 15Apr 9Apr 5Apr 2Mar 30Mar 26Mar 21Mar 17Mar 12

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 12Sep 16Sep 19Sep 22Sep 25Sep 28Oct 1Oct 4Oct 9
32°FSep 21Sep 24Sep 28Oct 1Oct 4Oct 7Oct 10Oct 14Oct 18
28°FSep 30Oct 5Oct 8Oct 12Oct 15Oct 19Oct 22Oct 25Oct 29
24°FOct 12Oct 17Oct 21Oct 24Oct 27Oct 29Nov 1Nov 3Nov 8
20°FOct 22Oct 26Oct 30Nov 1Nov 2Nov 5Nov 8Nov 12Nov 17
16°FOct 30Nov 2Nov 4Nov 8Nov 11Nov 14Nov 17Nov 20Nov 26

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°F152146141138135131127124117
32°F172166161157153149144140134
28°F194187183178174170166161155
24°F215208203198194190186181175
20°F233225219215210206202197189
16°F250241235230226222217211205

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
8,066
Cooling degree days, base 65°F
588
Growing degree days, base 40°F
4,441
Growing degree days, base 45°F
3,437
Growing degree days, base 50°F
2,542
Growing degree days, base 55°F
1,765
Growing degree days, base 60°F
1,109

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,58200
February1,30300
March1,07108
April635255
May28433254
June51138537
July14212663
August33144577
September17554343
October545595
November975010
December1,40000

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 28.4 km from Adrian. 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 USC00219170 (Worthington 2 Nne). Public domain.