Pinnacle climate

Pinnacle Frost Dates and Growing Season

NOAA 1991-2020 normals for Pfafftown, 20.1 km from Pinnacle, elevation 950 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pfafftown. 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 9 and the first fall freeze around October 31, a growing season of about 204 days.

Median at 36°F
last April 21, first October 23
Median at 32°F
last April 9, first October 31
Median at 28°F
last March 28, 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 8May 1Apr 27Apr 24Apr 21Apr 19Apr 16Apr 13Apr 8
32°FApr 23Apr 18Apr 15Apr 13Apr 9Apr 5Apr 2Mar 31Mar 25
28°FApr 12Apr 6Apr 3Mar 31Mar 28Mar 25Mar 22Mar 18Mar 12
24°FApr 2Mar 29Mar 25Mar 21Mar 18Mar 15Mar 11Mar 6Feb 28
20°FMar 23Mar 17Mar 13Mar 9Mar 5Mar 1Feb 26Feb 20Feb 12
16°FMar 14Mar 5Mar 1Feb 24Feb 19Feb 13Feb 7Feb 1Jan 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°FOct 11Oct 15Oct 18Oct 20Oct 23Oct 25Oct 27Oct 30Nov 2
32°FOct 20Oct 23Oct 26Oct 29Oct 31Nov 1Nov 4Nov 6Nov 11
28°FOct 28Nov 1Nov 3Nov 5Nov 8Nov 10Nov 14Nov 18Nov 24
24°FNov 4Nov 8Nov 11Nov 15Nov 18Nov 22Nov 27Dec 1Dec 8
20°FNov 15Nov 20Nov 25Nov 30Dec 3Dec 6Dec 12Dec 20Dec 31
16°FNov 30Dec 4Dec 9Dec 14Dec 22Dec 27Jan 2Jan 8Jan 17

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°F201195190187184180176171165
32°F224217213208204200196191185
28°F246240234230226222217212206
24°F273265259253248243239234227
20°F303294287281275269263257250
16°F336327318311305299293285274

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
99% 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
4,036
Cooling degree days, base 65°F
1,382
Growing degree days, base 40°F
6,879
Growing degree days, base 45°F
5,442
Growing degree days, base 50°F
4,176
Growing degree days, base 55°F
3,091
Growing degree days, base 60°F
2,163

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January857010
February705014
March549269
April26314228
May88107485
June5273718
July0412877
August0363827
September36180594
October23330277
November522164
December778013

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 20.1 km from Pinnacle. 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 USC00316686 (Pfafftown). Public domain.