Benton climate

Benton Frost Dates and Growing Season

NOAA 1991-2020 normals for Rend Lake Dam, 7.7 km from Benton, elevation 455 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rend Lake Dam. 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 4 and the first fall freeze around October 27, a growing season of about 204 days.

Median at 36°F
last April 15, first October 18
Median at 32°F
last April 4, first October 27
Median at 28°F
last March 26, first November 5

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 1Apr 26Apr 22Apr 19Apr 15Apr 11Apr 8Apr 5Mar 31
32°FApr 19Apr 14Apr 10Apr 7Apr 4Apr 2Mar 31Mar 27Mar 21
28°FApr 9Apr 4Mar 31Mar 29Mar 26Mar 23Mar 19Mar 16Mar 10
24°FMar 30Mar 25Mar 22Mar 18Mar 15Mar 12Mar 8Mar 4Feb 28
20°FMar 22Mar 17Mar 13Mar 9Mar 6Mar 3Feb 28Feb 25Feb 18
16°FMar 15Mar 8Mar 4Mar 1Feb 27Feb 24Feb 20Feb 15Feb 8

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 5Oct 10Oct 13Oct 16Oct 18Oct 20Oct 22Oct 25Oct 28
32°FOct 16Oct 20Oct 23Oct 25Oct 27Oct 29Oct 31Nov 3Nov 8
28°FOct 25Oct 30Nov 1Nov 2Nov 5Nov 8Nov 11Nov 15Nov 23
24°FNov 2Nov 5Nov 9Nov 12Nov 16Nov 20Nov 25Nov 30Dec 4
20°FNov 9Nov 14Nov 19Nov 24Nov 29Dec 2Dec 5Dec 11Dec 19
16°FNov 17Nov 26Dec 1Dec 5Dec 10Dec 15Dec 20Dec 25Jan 1

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°F202196192187183180176171163
32°F222216211207204200197191185
28°F246238232227223219215210203
24°F269261256250245241236230223
20°F291282276271266261256250243
16°F314305299292287282276270260

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
4,734
Cooling degree days, base 65°F
1,449
Growing degree days, base 40°F
6,722
Growing degree days, base 45°F
5,386
Growing degree days, base 50°F
4,193
Growing degree days, base 55°F
3,144
Growing degree days, base 60°F
2,234

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,06304
February862010
March622260
April27421237
May91128505
June3316763
July0411876
August1362826
September42168576
October26640268
November592362
December91908

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 7.7 km from Benton. 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 USC00117187 (Rend Lake Dam). Public domain.