Rennerdale climate

Rennerdale Frost Dates and Growing Season

NOAA 1991-2020 normals for Pittsburgh Intl AP, 11.5 km from Rennerdale, elevation 1203 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pittsburgh Intl AP. 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 23 and the first fall freeze around October 23, a growing season of about 181 days.

Median at 36°F
last May 4, first October 12
Median at 32°F
last April 23, first October 23
Median at 28°F
last April 12, first November 4

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 17May 11May 8May 4May 1Apr 28Apr 24Apr 19
32°FMay 12May 5May 1Apr 27Apr 23Apr 21Apr 18Apr 15Apr 9
28°FApr 27Apr 21Apr 18Apr 15Apr 12Apr 8Apr 5Apr 2Mar 28
24°FApr 14Apr 9Apr 5Apr 2Mar 31Mar 29Mar 25Mar 21Mar 15
20°FApr 3Mar 30Mar 27Mar 24Mar 21Mar 18Mar 15Mar 10Mar 4
16°FMar 27Mar 22Mar 18Mar 15Mar 11Mar 8Mar 4Feb 28Feb 22

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 30Oct 4Oct 6Oct 9Oct 12Oct 15Oct 17Oct 21Oct 25
32°FOct 9Oct 14Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 6
28°FOct 21Oct 26Oct 30Nov 1Nov 4Nov 6Nov 9Nov 13Nov 18
24°FNov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 21Nov 25Dec 1
20°FNov 9Nov 14Nov 18Nov 22Nov 26Nov 30Dec 3Dec 8Dec 14
16°FNov 20Nov 26Dec 1Dec 5Dec 9Dec 14Dec 19Dec 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°F178172168163159155150146138
32°F202194190185181177173167160
28°F227219215210207203199193186
24°F251243237233228225220215208
20°F274266260256252247242236229
16°F298290283278273268263256249

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
5,572
Cooling degree days, base 65°F
797
Growing degree days, base 40°F
5,498
Growing degree days, base 45°F
4,273
Growing degree days, base 50°F
3,191
Growing degree days, base 55°F
2,247
Growing degree days, base 60°F
1,445

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12006
February94107
March785138
April4139144
May17256358
June30161581
July3256718
August7219677
September8685450
October37111168
November672038
December97208

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 Rennerdale. 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 USW00094823 (Pittsburgh Intl AP). Public domain.