Rouzerville climate

Rouzerville Frost Dates and Growing Season

NOAA 1991-2020 normals for S Mtn, 12.9 km from Rouzerville, elevation 1520 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for S Mtn. 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 27 and the first fall freeze around October 20, a growing season of about 177 days.

Median at 36°F
last May 7, first October 8
Median at 32°F
last April 27, first October 20
Median at 28°F
last April 13, first November 1

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 5May 1Apr 29Apr 24
32°FMay 14May 7May 3Apr 30Apr 27Apr 24Apr 20Apr 17Apr 13
28°FMay 1Apr 24Apr 19Apr 16Apr 13Apr 10Apr 7Apr 3Mar 31
24°FApr 13Apr 9Apr 6Apr 3Apr 1Mar 31Mar 28Mar 24Mar 19
20°FApr 4Mar 31Mar 29Mar 26Mar 22Mar 19Mar 16Mar 13Mar 7
16°FMar 26Mar 22Mar 19Mar 16Mar 12Mar 9Mar 6Mar 2Feb 24

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 24Sep 30Oct 3Oct 5Oct 8Oct 11Oct 14Oct 17Oct 21
32°FOct 6Oct 11Oct 15Oct 17Oct 20Oct 23Oct 26Oct 29Nov 2
28°FOct 17Oct 22Oct 26Oct 29Nov 1Nov 3Nov 6Nov 10Nov 14
24°FOct 30Nov 2Nov 5Nov 9Nov 11Nov 14Nov 17Nov 21Nov 28
20°FNov 7Nov 12Nov 16Nov 19Nov 22Nov 28Dec 1Dec 5Dec 15
16°FNov 18Nov 24Nov 30Dec 3Dec 8Dec 13Dec 18Dec 23Dec 31

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°F173166161158154149144139132
32°F196190186181177173168163155
28°F221215210206202198193186178
24°F246237233228224220216212205
20°F271262255250246241236231224
16°F298289283277271265260253245

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
5,995
Cooling degree days, base 65°F
570
Growing degree days, base 40°F
4,954
Growing degree days, base 45°F
3,782
Growing degree days, base 50°F
2,756
Growing degree days, base 55°F
1,873
Growing degree days, base 60°F
1,142

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14503
February97905
March863019
April490597
May22127286
June45114519
July8198656
August15161611
September11959392
October4096139
November704025
December99805

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 12.9 km from Rouzerville. 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 USC00368308 (S Mtn). Public domain.