Shenandoah Junction climate

Shenandoah Junction Frost Dates and Growing Season

NOAA 1991-2020 normals for Sharpsburg 5 S, 11.4 km from Shenandoah Junction, elevation 400 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sharpsburg 5 S. 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 26 and the first fall freeze around October 18, a growing season of about 175 days.

Median at 36°F
last May 7, first October 9
Median at 32°F
last April 26, first October 18
Median at 28°F
last April 11, first October 30

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 24May 19May 14May 11May 7May 3Apr 30Apr 27Apr 22
32°FMay 15May 8May 3Apr 30Apr 26Apr 23Apr 19Apr 16Apr 11
28°FApr 29Apr 21Apr 17Apr 14Apr 11Apr 8Apr 5Apr 2Mar 29
24°FApr 12Apr 7Apr 4Apr 2Mar 31Mar 29Mar 25Mar 21Mar 14
20°FApr 2Mar 30Mar 26Mar 23Mar 19Mar 16Mar 12Mar 8Mar 1
16°FMar 25Mar 19Mar 15Mar 11Mar 7Mar 4Feb 28Feb 23Feb 16

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 26Sep 30Oct 3Oct 5Oct 9Oct 11Oct 14Oct 17Oct 22
32°FOct 5Oct 9Oct 13Oct 16Oct 18Oct 22Oct 25Oct 30Nov 2
28°FOct 14Oct 20Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 13
24°FOct 27Nov 1Nov 4Nov 6Nov 10Nov 13Nov 17Nov 21Nov 28
20°FNov 5Nov 11Nov 16Nov 20Nov 24Nov 28Dec 1Dec 6Dec 12
16°FNov 18Nov 25Dec 1Dec 4Dec 8Dec 13Dec 18Dec 23Dec 29

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°F173167161157153148144140132
32°F195189184179175171166161153
28°F221215210206201197192186178
24°F246239234229224220216211204
20°F275266260255249245240234226
16°F303295289283277272267260252

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
5,274
Cooling degree days, base 65°F
894
Growing degree days, base 40°F
5,656
Growing degree days, base 45°F
4,406
Growing degree days, base 50°F
3,306
Growing degree days, base 55°F
2,358
Growing degree days, base 60°F
1,554

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,04904
February87906
March752032
April41111138
May17252354
June24177603
July2288752
August5248708
September75102478
October34315184
November633039
December92909

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 11.4 km from Shenandoah Junction. 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 USC00188207 (Sharpsburg 5 S). Public domain.