Mayodan climate

Mayodan Frost Dates and Growing Season

NOAA 1991-2020 normals for Danbury, 19.1 km from Mayodan, elevation 1019 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Danbury. 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 11 and the first fall freeze around October 30, a growing season of about 202 days.

Median at 36°F
last April 22, first October 22
Median at 32°F
last April 11, first October 30
Median at 28°F
last March 27, first November 9

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 8May 2Apr 29Apr 25Apr 22Apr 19Apr 16Apr 13Apr 8
32°FApr 29Apr 22Apr 17Apr 13Apr 11Apr 8Apr 4Mar 31Mar 25
28°FApr 12Apr 6Apr 2Mar 30Mar 27Mar 23Mar 19Mar 15Mar 7
24°FMar 29Mar 23Mar 19Mar 16Mar 12Mar 8Mar 3Feb 27Feb 18
20°FMar 18Mar 12Mar 6Mar 2Feb 27Feb 21Feb 14Feb 7Jan 31
16°FMar 9Feb 28Feb 19Feb 11Feb 5Jan 31Jan 26Jan 19Jan 9

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 9Oct 13Oct 16Oct 19Oct 22Oct 24Oct 27Oct 30Nov 3
32°FOct 18Oct 22Oct 25Oct 28Oct 30Nov 1Nov 4Nov 7Nov 12
28°FOct 26Oct 31Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 26
24°FNov 6Nov 11Nov 14Nov 18Nov 22Nov 26Dec 1Dec 5Dec 14
20°FNov 17Nov 24Nov 30Dec 4Dec 9Dec 16Dec 23Dec 31Jan 9
16°FDec 3Dec 12Dec 22Dec 30Jan 2Jan 7Jan 13Jan 18Jan 25

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°F201196191187183179175169161
32°F223216211207202199194188180
28°F251243237231227222218213206
24°F288276268261256250245238231
20°F324311303295288281273267257
16°F356344335330323314306298287

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
93% 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
3,911
Cooling degree days, base 65°F
1,298
Growing degree days, base 40°F
6,891
Growing degree days, base 45°F
5,440
Growing degree days, base 50°F
4,161
Growing degree days, base 55°F
3,048
Growing degree days, base 60°F
2,094

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January829015
February674021
March534291
April26323243
May87102482
June9261702
July0385849
August1330794
September32164582
October23229280
November514277
December736025

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 19.1 km from Mayodan. 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 USC00312238 (Danbury). Public domain.