Summitville climate

Summitville Frost Dates and Growing Season

NOAA 1991-2020 normals for Elwood, 18 km from Summitville, elevation 866 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Elwood. 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 24 and the first fall freeze around October 18, a growing season of about 175 days.

Median at 36°F
last May 5, first October 6
Median at 32°F
last April 24, first October 18
Median at 28°F
last April 12, first October 30

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 19May 15May 11May 8May 5May 2Apr 29Apr 24Apr 20
32°FMay 10May 5May 1Apr 28Apr 24Apr 21Apr 18Apr 14Apr 8
28°FApr 30Apr 23Apr 19Apr 15Apr 12Apr 8Apr 5Apr 2Mar 28
24°FApr 15Apr 8Apr 5Apr 2Mar 31Mar 28Mar 24Mar 20Mar 14
20°FApr 4Mar 31Mar 27Mar 23Mar 20Mar 16Mar 13Mar 9Mar 3
16°FMar 28Mar 21Mar 16Mar 13Mar 10Mar 6Mar 3Feb 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 4Oct 6Oct 9Oct 12Oct 16Oct 21
32°FOct 4Oct 9Oct 13Oct 16Oct 18Oct 21Oct 23Oct 27Nov 1
28°FOct 15Oct 20Oct 24Oct 27Oct 30Nov 1Nov 4Nov 6Nov 12
24°FOct 28Nov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 21Nov 27
20°FNov 5Nov 9Nov 13Nov 18Nov 22Nov 25Nov 29Dec 3Dec 10
16°FNov 11Nov 19Nov 24Nov 28Dec 1Dec 4Dec 9Dec 15Dec 22

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°F173167162158154149145141134
32°F194188184179175172167162154
28°F220213208203199196192186178
24°F247239233227223219215210202
20°F270262256251246242237230224
16°F292283276271266261256250241

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
5,945
Cooling degree days, base 65°F
858
Growing degree days, base 40°F
5,422
Growing degree days, base 45°F
4,244
Growing degree days, base 50°F
3,198
Growing degree days, base 55°F
2,285
Growing degree days, base 60°F
1,502

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21601
February99902
March809235
April4468125
May17366368
June28193615
July5262722
August11220674
September9594451
October38614167
November719133
December1,05704

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 18 km from Summitville. 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 USC00122638 (Elwood). Public domain.