Benson climate

Benson Frost Dates and Growing Season

NOAA 1991-2020 normals for Dunn 4 Nw, 14.1 km from Benson, elevation 200 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dunn 4 Nw. 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 28 and the first fall freeze around November 7, a growing season of about 226 days.

Median at 36°F
last April 6, first October 30
Median at 32°F
last March 28, first November 7
Median at 28°F
last March 14, first November 19

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

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 17Oct 22Oct 25Oct 27Oct 30Nov 1Nov 3Nov 6Nov 10
32°FOct 26Oct 31Nov 2Nov 4Nov 7Nov 9Nov 12Nov 17Nov 23
28°FNov 4Nov 9Nov 12Nov 15Nov 19Nov 23Nov 28Dec 2Dec 10
24°FNov 14Nov 20Nov 26Dec 1Dec 5Dec 10Dec 18Dec 28Jan 6
20°FNov 27Dec 6Dec 13Dec 21Dec 30Jan 2Jan 8Jan 14Jan 26
16°FDec 13Dec 26Jan 1Jan 5Jan 11Jan 15Jan 19Jan 27Feb 3

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°F225218213209205201198193185
32°F249242235230226221217212205
28°F279270262257251246241234227
24°F319306298290284277269261253
20°F355342334327320310303295281
16°F365365365360350342335331316

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
94% of years
16°F or colder
66% 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
2,912
Cooling degree days, base 65°F
1,971
Growing degree days, base 40°F
8,348
Growing degree days, base 45°F
6,750
Growing degree days, base 50°F
5,311
Growing degree days, base 55°F
4,033
Growing degree days, base 60°F
2,920

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January678145
February535359
March39313166
April15562366
May37189617
June2386834
July0505970
August0453918
September9278718
October13370407
November3799147
December591465

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 14.1 km from Benson. 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 USC00312500 (Dunn 4 Nw). Public domain.