Benton County climate

Benton County Frost Dates and Growing Season

NOAA 1991-2020 normals for Ashland, 4.4 km from Benton County, elevation 603 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ashland. 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 March 29 and the first fall freeze around November 6, a growing season of about 224 days.

Median at 36°F
last April 8, first October 27
Median at 32°F
last March 29, first November 6
Median at 28°F
last March 11, first November 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°FApr 26Apr 19Apr 15Apr 11Apr 8Apr 5Apr 2Mar 29Mar 22
32°FApr 15Apr 8Apr 4Apr 1Mar 29Mar 24Mar 19Mar 14Mar 6
28°FApr 3Mar 26Mar 20Mar 16Mar 11Mar 7Mar 3Feb 27Feb 20
24°FMar 18Mar 12Mar 6Mar 2Feb 28Feb 23Feb 17Feb 9Feb 2
20°FMar 8Mar 2Feb 26Feb 18Feb 11Feb 5Jan 31Jan 24Jan 14
16°FFeb 28Feb 16Feb 6Feb 1Jan 29Jan 22Jan 15Jan 9Jan 2

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 14Oct 19Oct 22Oct 24Oct 27Oct 29Nov 1Nov 5Nov 9
32°FOct 22Oct 28Nov 1Nov 3Nov 6Nov 9Nov 13Nov 18Nov 25
28°FNov 2Nov 8Nov 12Nov 16Nov 20Nov 24Nov 30Dec 3Dec 10
24°FNov 14Nov 20Nov 26Dec 1Dec 4Dec 8Dec 15Dec 22Jan 1
20°FNov 25Dec 3Dec 10Dec 18Dec 24Dec 30Jan 3Jan 10Jan 19
16°FDec 7Dec 22Dec 30Jan 1Jan 6Jan 10Jan 16Jan 21Feb 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°F224217212207202197193188181
32°F251243236230224219213208200
28°F280270264258252246241235224
24°F311301293286279274268261250
20°F346334327317309303296287276
16°F365365358349341334327314303

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
97% of years
16°F or colder
78% 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
3,498
Cooling degree days, base 65°F
1,694
Growing degree days, base 40°F
7,692
Growing degree days, base 45°F
6,191
Growing degree days, base 50°F
4,831
Growing degree days, base 55°F
3,626
Growing degree days, base 60°F
2,584

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January810026
February620146
March4468142
April19443317
May52168582
June1331780
July0433897
August0408872
September18237669
October17860360
November4686105
December710036

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 4.4 km from Benton County. 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 USC00220290 (Ashland). Public domain.