Butler climate

Butler Frost Dates and Growing Season

NOAA 1991-2020 normals for Danville 2 W, 19.5 km from Butler, elevation 970 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Danville 2 W. 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 2 and the first fall freeze around October 8, a growing season of about 157 days.

Median at 36°F
last May 14, first September 29
Median at 32°F
last May 2, first October 8
Median at 28°F
last April 22, 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 29May 24May 20May 17May 14May 9May 6May 2Apr 28
32°FMay 19May 14May 9May 6May 2Apr 30Apr 27Apr 24Apr 20
28°FMay 9May 3Apr 30Apr 26Apr 22Apr 20Apr 17Apr 13Apr 9
24°FApr 25Apr 20Apr 17Apr 14Apr 10Apr 7Apr 4Apr 1Mar 28
20°FApr 15Apr 8Apr 4Apr 1Mar 31Mar 28Mar 23Mar 19Mar 14
16°FApr 1Mar 29Mar 24Mar 20Mar 18Mar 14Mar 10Mar 6Mar 1

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 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 4Oct 7Oct 11
32°FSep 24Sep 30Oct 3Oct 5Oct 8Oct 11Oct 14Oct 17Oct 21
28°FOct 6Oct 11Oct 14Oct 17Oct 20Oct 22Oct 25Oct 28Nov 1
24°FOct 18Oct 22Oct 26Oct 30Nov 1Nov 3Nov 6Nov 10Nov 16
20°FOct 30Nov 2Nov 6Nov 10Nov 12Nov 16Nov 19Nov 23Nov 29
16°FNov 9Nov 14Nov 18Nov 22Nov 26Nov 29Dec 3Dec 8Dec 15

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°F157151146142138133129124117
32°F174168164161157153148143136
28°F198192187182178174169165157
24°F223216210206202198194189182
20°F250244236231227222218212206
16°F278269262258252247242236228

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
6,344
Cooling degree days, base 65°F
558
Growing degree days, base 40°F
4,810
Growing degree days, base 45°F
3,669
Growing degree days, base 50°F
2,673
Growing degree days, base 55°F
1,819
Growing degree days, base 60°F
1,108

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22402
February1,03602
March864021
April509288
May23833281
June50124524
July11190643
August20150595
September13553374
October4496118
November755020
December1,05404

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 19.5 km from Butler. 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 USC00332044 (Danville 2 W). Public domain.