Grant City climate

Grant City Frost Dates and Growing Season

NOAA 1991-2020 normals for Grant City 5WSW, 7.8 km from Grant City, elevation 1089 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Grant City 5WSW. 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 20 and the first fall freeze around October 19, a growing season of about 181 days.

Median at 36°F
last May 1, first October 8
Median at 32°F
last April 20, first October 19
Median at 28°F
last April 9, first October 28

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 15May 9May 6May 4May 1Apr 29Apr 25Apr 21Apr 16
32°FMay 6May 1Apr 28Apr 24Apr 20Apr 17Apr 14Apr 10Apr 5
28°FApr 24Apr 19Apr 15Apr 12Apr 9Apr 5Apr 3Mar 31Mar 25
24°FApr 16Apr 10Apr 5Apr 2Mar 31Mar 28Mar 24Mar 19Mar 14
20°FApr 6Mar 31Mar 28Mar 24Mar 20Mar 17Mar 14Mar 9Mar 5
16°FMar 29Mar 21Mar 18Mar 14Mar 11Mar 8Mar 5Mar 2Feb 25

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 24Sep 29Oct 2Oct 5Oct 8Oct 11Oct 14Oct 17Oct 22
32°FOct 4Oct 10Oct 13Oct 16Oct 19Oct 21Oct 24Oct 27Oct 31
28°FOct 16Oct 20Oct 23Oct 26Oct 28Oct 31Nov 1Nov 4Nov 9
24°FOct 23Oct 28Oct 31Nov 2Nov 4Nov 7Nov 10Nov 13Nov 19
20°FNov 1Nov 3Nov 7Nov 9Nov 12Nov 15Nov 19Nov 24Dec 1
16°FNov 6Nov 12Nov 16Nov 19Nov 23Nov 26Nov 30Dec 4Dec 9

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°F180173168164160156152146139
32°F201194189185181176172167161
28°F223215210205203198194190183
24°F243234229224220215211206201
20°F261252246242238233228223216
16°F280271265260255251246240233

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
6,085
Cooling degree days, base 65°F
1,029
Growing degree days, base 40°F
5,651
Growing degree days, base 45°F
4,466
Growing degree days, base 50°F
3,409
Growing degree days, base 55°F
2,483
Growing degree days, base 60°F
1,695

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30000
February1,03204
March772139
April4195137
May17854353
June13214651
July2351813
August5280741
September90111473
October37813175
November767022
December1,13101

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 7.8 km from Grant City. 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 USC00233375 (Grant City 5WSW). Public domain.