Scottdale climate

Scottdale Frost Dates and Growing Season

NOAA 1991-2020 normals for Connellsville 2 Ssw, 11.5 km from Scottdale, elevation 900 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Connellsville 2 Ssw. 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 27, a growing season of about 187 days.

Median at 36°F
last May 3, first October 17
Median at 32°F
last April 22, first October 27
Median at 28°F
last April 7, first November 8

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 22May 16May 11May 8May 3Apr 30Apr 26Apr 23Apr 19
32°FMay 11May 5Apr 30Apr 25Apr 22Apr 19Apr 16Apr 12Apr 6
28°FApr 24Apr 18Apr 14Apr 10Apr 7Apr 4Apr 2Mar 30Mar 23
24°FApr 9Apr 4Apr 1Mar 30Mar 27Mar 23Mar 19Mar 16Mar 10
20°FMar 30Mar 25Mar 21Mar 18Mar 15Mar 12Mar 8Mar 4Feb 25
16°FMar 21Mar 17Mar 12Mar 8Mar 6Mar 2Feb 26Feb 20Feb 12

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 4Oct 8Oct 11Oct 14Oct 17Oct 19Oct 22Oct 25Oct 30
32°FOct 14Oct 19Oct 22Oct 25Oct 27Oct 31Nov 1Nov 5Nov 10
28°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 11Nov 13Nov 17Nov 23
24°FNov 4Nov 9Nov 12Nov 14Nov 17Nov 22Nov 27Dec 2Dec 9
20°FNov 12Nov 17Nov 24Nov 29Dec 2Dec 6Dec 11Dec 17Dec 25
16°FNov 25Dec 1Dec 8Dec 12Dec 19Dec 23Dec 28Jan 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°F185179174169165161156151144
32°F209203197193187183178173165
28°F234226222217214210206200192
24°F262254248243238233228223217
20°F289280273269262257251245237
16°F311303298292287281276270261

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
5,532
Cooling degree days, base 65°F
787
Growing degree days, base 40°F
5,484
Growing degree days, base 45°F
4,255
Growing degree days, base 50°F
3,177
Growing degree days, base 55°F
2,242
Growing degree days, base 60°F
1,444

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,10004
February93805
March794135
April4367128
May17855360
June24141567
July3251713
August5223683
September8294463
October35615179
November672034
December94406

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 11.5 km from Scottdale. 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 USC00361726 (Connellsville 2 Ssw). Public domain.