Bluffs climate

Bluffs Frost Dates and Growing Season

NOAA 1991-2020 normals for Winchester, 14.8 km from Bluffs, elevation 551 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Winchester. 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 18 and the first fall freeze around October 20, a growing season of about 183 days.

Median at 36°F
last April 30, first October 8
Median at 32°F
last April 18, first October 20
Median at 28°F
last April 5, first October 29

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

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°FSep 24Sep 29Oct 2Oct 6Oct 8Oct 11Oct 14Oct 17Oct 21
32°FOct 5Oct 10Oct 14Oct 17Oct 20Oct 22Oct 24Oct 27Oct 31
28°FOct 16Oct 21Oct 24Oct 27Oct 29Nov 1Nov 3Nov 7Nov 12
24°FOct 29Nov 1Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 25
20°FNov 6Nov 9Nov 12Nov 16Nov 20Nov 24Nov 28Dec 1Dec 7
16°FNov 12Nov 19Nov 23Nov 27Dec 1Dec 3Dec 7Dec 12Dec 19

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°F180175169166161157153148141
32°F202197192186183179174168160
28°F225217213210206202198193184
24°F250242237233228224219215208
20°F273264259255250246241236229
16°F293284278271267262258252245

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
5,485
Cooling degree days, base 65°F
1,130
Growing degree days, base 40°F
5,992
Growing degree days, base 45°F
4,765
Growing degree days, base 50°F
3,673
Growing degree days, base 55°F
2,695
Growing degree days, base 60°F
1,843

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18502
February94606
March731353
April37113171
May13285424
June14245681
July1341804
August4296758
September68126510
October32822215
November686142
December1,02006

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 14.8 km from Bluffs. 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 USC00119331 (Winchester). Public domain.