Butler County climate

Butler County Frost Dates and Growing Season

NOAA 1991-2020 normals for David City, 2.6 km from Butler County, elevation 1610 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for David City. 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 26 and the first fall freeze around October 11, a growing season of about 168 days.

Median at 36°F
last May 5, first October 3
Median at 32°F
last April 26, first October 11
Median at 28°F
last April 17, first October 20

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 17May 13May 10May 7May 5May 3May 1Apr 28Apr 22
32°FMay 8May 4May 2Apr 30Apr 26Apr 23Apr 21Apr 17Apr 12
28°FMay 1Apr 26Apr 23Apr 19Apr 17Apr 14Apr 10Apr 7Apr 3
24°FApr 23Apr 18Apr 14Apr 10Apr 7Apr 4Apr 2Mar 30Mar 23
20°FApr 15Apr 9Apr 6Apr 3Mar 31Mar 27Mar 22Mar 17Mar 11
16°FApr 6Apr 1Mar 29Mar 24Mar 20Mar 16Mar 12Mar 8Mar 3

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 21Sep 25Sep 28Sep 30Oct 3Oct 5Oct 8Oct 12Oct 16
32°FSep 28Oct 1Oct 5Oct 8Oct 11Oct 14Oct 17Oct 19Oct 23
28°FOct 3Oct 10Oct 14Oct 17Oct 20Oct 23Oct 25Oct 28Nov 1
24°FOct 14Oct 20Oct 23Oct 26Oct 30Nov 1Nov 4Nov 8Nov 12
20°FOct 23Oct 29Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 23
16°FOct 31Nov 5Nov 9Nov 12Nov 15Nov 19Nov 23Nov 28Dec 2

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°F166161157153150147143138132
32°F187180175171168164160154148
28°F205199194190187183178173165
24°F227219213209205202196190182
20°F246237231227222218214208199
16°F262254249244239235230223215

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
6,641
Cooling degree days, base 65°F
938
Growing degree days, base 40°F
5,319
Growing degree days, base 45°F
4,199
Growing degree days, base 50°F
3,201
Growing degree days, base 55°F
2,319
Growing degree days, base 60°F
1,564

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,35200
February1,10002
March858128
April4936106
May20057341
June26197621
July4312773
August11251705
September106103452
October42712155
November837018
December1,22800

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 2.6 km from Butler 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 USC00252205 (David City). Public domain.