Galena climate

Galena Frost Dates and Growing Season

NOAA 1991-2020 normals for Westerville, 11.2 km from Galena, elevation 802 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Westerville. 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 22 and the first fall freeze around October 24, a growing season of about 183 days.

Median at 36°F
last May 2, first October 12
Median at 32°F
last April 22, first October 24
Median at 28°F
last April 9, first November 3

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 21May 14May 10May 5May 2Apr 29Apr 26Apr 23Apr 19
32°FMay 10May 2Apr 28Apr 24Apr 22Apr 20Apr 17Apr 13Apr 9
28°FApr 24Apr 20Apr 17Apr 13Apr 9Apr 6Apr 3Mar 31Mar 27
24°FApr 11Apr 6Apr 3Mar 31Mar 29Mar 26Mar 23Mar 19Mar 13
20°FApr 1Mar 29Mar 24Mar 20Mar 18Mar 15Mar 11Mar 7Feb 28
16°FMar 24Mar 19Mar 15Mar 11Mar 8Mar 5Mar 1Feb 25Feb 16

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 27Oct 3Oct 6Oct 9Oct 12Oct 14Oct 16Oct 20Oct 25
32°FOct 10Oct 14Oct 18Oct 21Oct 24Oct 26Oct 30Nov 1Nov 5
28°FOct 21Oct 26Oct 30Nov 1Nov 3Nov 6Nov 9Nov 12Nov 18
24°FNov 1Nov 4Nov 7Nov 10Nov 14Nov 17Nov 21Nov 26Dec 2
20°FNov 10Nov 14Nov 18Nov 23Nov 27Dec 1Dec 5Dec 9Dec 17
16°FNov 18Nov 25Dec 1Dec 4Dec 8Dec 13Dec 17Dec 22Dec 28

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°F180174170166162158153148139
32°F201195191187183179175169161
28°F228220215211207203199194187
24°F255247241237231226222216210
20°F278270264259254249243237229
16°F301293286280275271265259251

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
5,108
Cooling degree days, base 65°F
1,096
Growing degree days, base 40°F
6,117
Growing degree days, base 45°F
4,841
Growing degree days, base 50°F
3,698
Growing degree days, base 55°F
2,691
Growing degree days, base 60°F
1,823

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08905
February89608
March707254
April34316190
May12592437
June15230664
July1323787
August3277739
September58134527
October30122226
November626151
December94409

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 11.2 km from Galena. 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 USC00338951 (Westerville). Public domain.