Carbon County climate

Carbon County Frost Dates and Growing Season

NOAA 1991-2020 normals for Lehighton 1SSW, 10.7 km from Carbon County, elevation 455 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lehighton 1SSW. 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 21 and the first fall freeze around October 23, a growing season of about 184 days.

Median at 36°F
last May 3, first October 11
Median at 32°F
last April 21, first October 23
Median at 28°F
last April 7, 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 20May 14May 10May 7May 3Apr 30Apr 28Apr 24Apr 19
32°FMay 9May 2Apr 28Apr 24Apr 21Apr 18Apr 15Apr 11Apr 7
28°FApr 22Apr 17Apr 12Apr 9Apr 7Apr 4Apr 2Mar 30Mar 24
24°FApr 8Apr 4Apr 2Mar 31Mar 29Mar 25Mar 22Mar 17Mar 13
20°FMar 31Mar 28Mar 23Mar 20Mar 17Mar 14Mar 10Mar 6Feb 28
16°FMar 22Mar 17Mar 13Mar 10Mar 7Mar 3Feb 28Feb 22Feb 15

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 1Oct 3Oct 6Oct 8Oct 11Oct 14Oct 17Oct 20Oct 25
32°FOct 7Oct 12Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 6
28°FOct 20Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 15Nov 19
24°FNov 3Nov 8Nov 12Nov 15Nov 17Nov 20Nov 24Nov 29Dec 3
20°FNov 13Nov 18Nov 22Nov 25Nov 29Dec 1Dec 5Dec 9Dec 16
16°FNov 24Nov 30Dec 4Dec 9Dec 13Dec 18Dec 23Dec 28Jan 5

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°F179172168163159155151146139
32°F206198193189184180176170162
28°F232224220215211207202197190
24°F256249244239235231226222216
20°F283274267262257253249243235
16°F306298292287281276271266257

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
6,027
Cooling degree days, base 65°F
581
Growing degree days, base 40°F
4,904
Growing degree days, base 45°F
3,756
Growing degree days, base 50°F
2,748
Growing degree days, base 55°F
1,885
Growing degree days, base 60°F
1,156

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17300
February99400
March854014
April471594
May19824301
June36107521
July4223683
August11163617
September11757392
October4263114
November723011
December1,02001

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 10.7 km from Carbon County. 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 USC00364934 (Lehighton 1SSW). Public domain.