Boone climate

Boone Frost Dates and Growing Season

NOAA 1991-2020 normals for Boone 1 Se, 2.6 km from Boone, elevation 3100 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Boone 1 Se. 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 May 2 and the first fall freeze around October 13, a growing season of about 163 days.

Median at 36°F
last May 14, first October 3
Median at 32°F
last May 2, first October 13
Median at 28°F
last April 19, first October 24

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 28May 24May 20May 16May 14May 10May 7May 3Apr 29
32°FMay 19May 14May 10May 6May 2Apr 30Apr 26Apr 22Apr 17
28°FMay 8May 1Apr 26Apr 22Apr 19Apr 15Apr 12Apr 8Apr 2
24°FApr 19Apr 13Apr 9Apr 6Apr 3Mar 31Mar 28Mar 23Mar 17
20°FApr 7Apr 2Mar 31Mar 26Mar 22Mar 19Mar 15Mar 11Mar 3
16°FMar 28Mar 22Mar 17Mar 14Mar 9Mar 5Mar 1Feb 23Feb 13

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 19Sep 23Sep 27Sep 30Oct 3Oct 5Oct 8Oct 11Oct 15
32°FSep 30Oct 4Oct 8Oct 10Oct 13Oct 15Oct 18Oct 22Oct 27
28°FOct 10Oct 15Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1Nov 5
24°FOct 21Oct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 12Nov 18
20°FOct 31Nov 4Nov 7Nov 12Nov 15Nov 18Nov 23Nov 29Dec 4
16°FNov 10Nov 16Nov 21Nov 26Dec 1Dec 3Dec 7Dec 15Dec 24

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°F162153149144140136132128121
32°F183177171167163159154148141
28°F208202196191187182176172162
24°F236228223218214210205199191
20°F264255248243238233228223215
16°F297285277270265259253247239

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
5,689
Cooling degree days, base 65°F
300
Growing degree days, base 40°F
4,683
Growing degree days, base 45°F
3,454
Growing degree days, base 50°F
2,401
Growing degree days, base 55°F
1,517
Growing degree days, base 60°F
808

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03802
February86104
March761022
April472195
May2399257
June6457443
July16120569
August2790529
September13522341
October4312113
November711022
December93506

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 2.6 km from Boone. 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 USC00310982 (Boone 1 Se). Public domain.