Saline County climate

Saline County Frost Dates and Growing Season

NOAA 1991-2020 normals for Harrisburg, 2 km from Saline County, elevation 365 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Harrisburg. 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 7 and the first fall freeze around October 26, a growing season of about 202 days.

Median at 36°F
last April 19, first October 16
Median at 32°F
last April 7, first October 26
Median at 28°F
last March 26, first November 6

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 5Apr 30Apr 26Apr 23Apr 19Apr 16Apr 13Apr 9Apr 3
32°FApr 25Apr 18Apr 14Apr 10Apr 7Apr 3Mar 31Mar 28Mar 21
28°FApr 12Apr 5Apr 1Mar 29Mar 26Mar 22Mar 18Mar 14Mar 7
24°FMar 30Mar 23Mar 19Mar 16Mar 12Mar 8Mar 5Mar 1Feb 21
20°FMar 17Mar 12Mar 8Mar 5Mar 2Feb 28Feb 22Feb 15Feb 8
16°FMar 11Mar 4Mar 1Feb 25Feb 19Feb 13Feb 8Feb 3Jan 27

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°FOct 1Oct 7Oct 11Oct 13Oct 16Oct 18Oct 21Oct 24Oct 28
32°FOct 10Oct 16Oct 21Oct 23Oct 26Oct 28Oct 31Nov 3Nov 8
28°FOct 23Oct 28Nov 1Nov 3Nov 6Nov 10Nov 13Nov 18Nov 25
24°FNov 3Nov 8Nov 12Nov 15Nov 19Nov 23Nov 28Dec 2Dec 9
20°FNov 13Nov 19Nov 23Nov 28Dec 2Dec 6Dec 11Dec 16Dec 23
16°FNov 23Dec 1Dec 5Dec 11Dec 16Dec 21Dec 25Dec 30Jan 6

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°F200193188184180176171166158
32°F224216211207202198194188180
28°F251242236231226222217211202
24°F279270263257252248243237229
20°F306297289283276271266259250
16°F330321313307301296289282271

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
4,299
Cooling degree days, base 65°F
1,522
Growing degree days, base 40°F
7,000
Growing degree days, base 45°F
5,624
Growing degree days, base 50°F
4,395
Growing degree days, base 55°F
3,303
Growing degree days, base 60°F
2,342

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January978011
February756017
March563894
April26036266
May66139538
June5322766
July0426891
August2370834
September37183596
October24234285
November548382
December842016

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 km from Saline 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 USC00113879 (Harrisburg). Public domain.