Rison climate

Rison Frost Dates and Growing Season

NOAA 1991-2020 normals for Rison, 1.2 km from Rison, elevation 280 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rison. 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 17 and the first fall freeze around November 14, a growing season of about 241 days.

Median at 36°F
last April 1, first November 2
Median at 32°F
last March 17, first November 14
Median at 28°F
last March 2, first November 28

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

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 18Oct 24Oct 27Oct 30Nov 2Nov 5Nov 8Nov 13Nov 20
32°FOct 30Nov 3Nov 7Nov 10Nov 14Nov 18Nov 22Nov 27Dec 4
28°FNov 8Nov 14Nov 20Nov 25Nov 28Dec 2Dec 6Dec 12Dec 22
24°FNov 23Nov 30Dec 5Dec 12Dec 19Dec 23Dec 29Jan 3Jan 12
20°FDec 6Dec 17Dec 25Dec 31Jan 3Jan 7Jan 11Jan 17Jan 31
16°FDec 13Dec 25Dec 31Jan 4Jan 9Jan 13Jan 19Jan 23Feb 4

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°F237230224219214210205200191
32°F269258252247241236230223214
28°F305293284277272266260252243
24°F339329318310304299292284272
20°F365361350342336329321311302
16°F365365365365365359348338325

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
99% of years
20°F or colder
84% of years
16°F or colder
48% 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
2,762
Cooling degree days, base 65°F
2,099
Growing degree days, base 40°F
8,653
Growing degree days, base 45°F
7,057
Growing degree days, base 50°F
5,591
Growing degree days, base 55°F
4,269
Growing degree days, base 60°F
3,100

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January673254
February507483
March32223220
April12173409
May24208650
June0405855
July0507972
August0485950
September10290730
October12589434
November37010163
December610371

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 1.2 km from Rison. 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 USC00036174 (Rison). Public domain.