Fincastle climate

Fincastle Frost Dates and Growing Season

NOAA 1991-2020 normals for Norris, 21.9 km from Fincastle, elevation 1110 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Norris. 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 22 and the first fall freeze around October 25, a growing season of about 184 days.

Median at 36°F
last May 2, first October 16
Median at 32°F
last April 22, first October 25
Median at 28°F
last April 7, first November 3

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 18May 12May 8May 5May 2Apr 30Apr 27Apr 23Apr 19
32°FMay 9May 2Apr 30Apr 26Apr 22Apr 18Apr 15Apr 11Apr 6
28°FApr 30Apr 22Apr 16Apr 11Apr 7Apr 4Mar 31Mar 27Mar 20
24°FApr 16Apr 7Apr 3Mar 30Mar 26Mar 21Mar 17Mar 11Mar 3
20°FMar 31Mar 24Mar 19Mar 15Mar 10Mar 5Feb 28Feb 24Feb 13
16°FMar 18Mar 10Mar 4Feb 28Feb 21Feb 13Feb 7Feb 2Jan 21

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 3Oct 8Oct 11Oct 13Oct 16Oct 17Oct 21Oct 24Oct 29
32°FOct 11Oct 15Oct 19Oct 22Oct 25Oct 27Oct 30Nov 1Nov 6
28°FOct 20Oct 26Oct 29Nov 1Nov 3Nov 6Nov 9Nov 13Nov 18
24°FNov 1Nov 5Nov 9Nov 12Nov 15Nov 18Nov 22Nov 27Dec 4
20°FNov 12Nov 18Nov 24Nov 28Dec 1Dec 5Dec 10Dec 18Dec 26
16°FNov 27Dec 2Dec 8Dec 14Dec 21Dec 25Dec 30Jan 4Jan 14

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°F183177172168165161157152146
32°F205199193188184179175169161
28°F230223216211207203198192182
24°F262252246239234229223216207
20°F299288279272266259253245235
16°F332322314306301294287278266

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
99% 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
4,385
Cooling degree days, base 65°F
974
Growing degree days, base 40°F
6,282
Growing degree days, base 45°F
4,903
Growing degree days, base 50°F
3,691
Growing degree days, base 55°F
2,637
Growing degree days, base 60°F
1,730

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January93607
February734013
March576169
April29412213
May10371436
June10192631
July1288752
August1264728
September39131542
October27516237
November582049
December834013

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 21.9 km from Fincastle. 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 USC00406619 (Norris). Public domain.