Mount Sidney climate

Mount Sidney Frost Dates and Growing Season

NOAA 1991-2020 normals for Staunton Wtp, 14.7 km from Mount Sidney, elevation 169 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Staunton Wtp. 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 15 and the first fall freeze around October 27, a growing season of about 191 days.

Median at 36°F
last May 1, first October 15
Median at 32°F
last April 15, first October 27
Median at 28°F
last April 3, first November 5

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 19May 12May 7May 4May 1Apr 27Apr 23Apr 19Apr 13
32°FMay 6Apr 30Apr 23Apr 19Apr 15Apr 11Apr 8Apr 5Apr 1
28°FApr 18Apr 12Apr 8Apr 5Apr 3Mar 31Mar 29Mar 25Mar 19
24°FApr 6Apr 2Mar 31Mar 27Mar 23Mar 19Mar 15Mar 11Mar 5
20°FMar 27Mar 22Mar 18Mar 14Mar 11Mar 7Mar 3Feb 27Feb 19
16°FMar 19Mar 14Mar 9Mar 4Feb 28Feb 24Feb 18Feb 9Feb 3

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 1Oct 5Oct 9Oct 13Oct 15Oct 19Oct 22Oct 25Oct 29
32°FOct 11Oct 16Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 9
28°FOct 22Oct 28Nov 1Nov 2Nov 5Nov 8Nov 11Nov 14Nov 20
24°FNov 1Nov 5Nov 8Nov 11Nov 16Nov 19Nov 24Nov 30Dec 6
20°FNov 10Nov 16Nov 21Nov 26Dec 1Dec 5Dec 9Dec 15Dec 23
16°FNov 23Dec 1Dec 6Dec 11Dec 16Dec 22Dec 27Jan 1Jan 10

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°F189182176172168162158152145
32°F211205200196191186182177167
28°F237229223219214211206201193
24°F264255249245240234229223215
20°F296285278270265260254247239
16°F320311304297292286280273263

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
4,834
Cooling degree days, base 65°F
892
Growing degree days, base 40°F
5,918
Growing degree days, base 45°F
4,598
Growing degree days, base 50°F
3,434
Growing degree days, base 55°F
2,431
Growing degree days, base 60°F
1,583

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January97509
February806011
March674150
April35715178
May14961383
June25178603
July2279742
August5236696
September70105487
October31717205
November590156
December865014

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 14.7 km from Mount Sidney. 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 USC00448062 (Staunton Wtp). Public domain.