Clarence climate

Clarence Frost Dates and Growing Season

NOAA 1991-2020 normals for Shelbina, 19.3 km from Clarence, elevation 747 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Shelbina. 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 21 and the first fall freeze around October 17, a growing season of about 177 days.

Median at 36°F
last May 1, first October 5
Median at 32°F
last April 21, first October 17
Median at 28°F
last April 11, 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 14May 9May 6May 3May 1Apr 29Apr 25Apr 22Apr 17
32°FMay 5Apr 30Apr 27Apr 23Apr 21Apr 18Apr 16Apr 13Apr 9
28°FApr 25Apr 21Apr 17Apr 14Apr 11Apr 8Apr 6Apr 1Mar 28
24°FApr 16Apr 10Apr 7Apr 4Apr 1Mar 30Mar 26Mar 20Mar 14
20°FApr 6Apr 1Mar 29Mar 25Mar 20Mar 16Mar 12Mar 8Mar 1
16°FMar 29Mar 23Mar 18Mar 14Mar 10Mar 7Mar 4Feb 28Feb 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 23Sep 28Oct 1Oct 3Oct 5Oct 9Oct 12Oct 15Oct 20
32°FOct 2Oct 6Oct 11Oct 14Oct 17Oct 20Oct 22Oct 26Oct 30
28°FOct 13Oct 17Oct 21Oct 25Oct 28Oct 30Nov 1Nov 4Nov 8
24°FOct 24Oct 29Nov 1Nov 3Nov 5Nov 7Nov 10Nov 15Nov 20
20°FNov 1Nov 5Nov 8Nov 11Nov 14Nov 18Nov 21Nov 26Dec 1
16°FNov 7Nov 12Nov 16Nov 20Nov 25Nov 28Dec 1Dec 6Dec 13

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°F175170164161158154150145138
32°F197191186181177174170165158
28°F219212207203199195191186181
24°F241234229223219214210204198
20°F264256249245241236231224217
16°F282274268263259254249243236

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
5,573
Cooling degree days, base 65°F
1,092
Growing degree days, base 40°F
5,919
Growing degree days, base 45°F
4,692
Growing degree days, base 50°F
3,600
Growing degree days, base 55°F
2,633
Growing degree days, base 60°F
1,792

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,19601
February95607
March725148
April38011163
May13977409
June13235672
July2346809
August4282742
September79120493
October33821210
November697142
December1,04304

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 19.3 km from Clarence. 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 USC00237720 (Shelbina). Public domain.