Brilliant climate

Brilliant Frost Dates and Growing Season

NOAA 1991-2020 normals for Winfield 2 Sw, 15.1 km from Brilliant, elevation 520 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Winfield 2 Sw. 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 November 1, a growing season of about 211 days.

Median at 36°F
last April 16, first October 24
Median at 32°F
last April 4, first November 1
Median at 28°F
last March 20, first November 11

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

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 12Oct 15Oct 19Oct 21Oct 24Oct 27Oct 30Nov 1Nov 6
32°FOct 19Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 19
28°FOct 29Nov 1Nov 4Nov 8Nov 11Nov 15Nov 19Nov 25Dec 1
24°FNov 7Nov 13Nov 18Nov 22Nov 27Dec 1Dec 3Dec 9Dec 21
20°FNov 19Nov 29Dec 1Dec 6Dec 11Dec 20Dec 27Jan 2Jan 10
16°FDec 3Dec 13Dec 23Dec 29Jan 1Jan 4Jan 10Jan 18Feb 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°F213206200195190185180175169
32°F237227221216211207203197189
28°F264255249244239234228222213
24°F298287280274267261256250242
20°F334321312305299291285277264
16°F365357345336331323314305294

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
99% of years
16°F or colder
90% 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
3,183
Cooling degree days, base 65°F
1,718
Growing degree days, base 40°F
7,916
Growing degree days, base 45°F
6,365
Growing degree days, base 50°F
4,962
Growing degree days, base 55°F
3,714
Growing degree days, base 60°F
2,632

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January738038
February567153
March3977159
April18436316
May45152572
June1331780
July0440905
August0422887
September14258694
October15763381
November4257127
December654251

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 15.1 km from Brilliant. 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 USC00018998 (Winfield 2 Sw). Public domain.