Warren County climate

Warren County Frost Dates and Growing Season

NOAA 1991-2020 normals for Conklingville Dam, 27.5 km from Warren County, elevation 808 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Conklingville Dam. 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 30 and the first fall freeze around October 16, a growing season of about 169 days.

Median at 36°F
last May 9, first October 4
Median at 32°F
last April 30, first October 16
Median at 28°F
last April 18, first October 31

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 23May 18May 14May 12May 9May 7May 4May 1Apr 28
32°FMay 13May 7May 4May 1Apr 30Apr 27Apr 25Apr 22Apr 18
28°FMay 1Apr 26Apr 23Apr 20Apr 18Apr 15Apr 12Apr 9Apr 5
24°FApr 19Apr 14Apr 11Apr 8Apr 6Apr 4Apr 2Apr 1Mar 28
20°FApr 9Apr 6Apr 4Apr 2Mar 31Mar 29Mar 26Mar 22Mar 17
16°FApr 5Apr 1Mar 30Mar 27Mar 24Mar 21Mar 18Mar 15Mar 11

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 22Sep 27Sep 30Oct 2Oct 4Oct 7Oct 10Oct 13Oct 18
32°FOct 2Oct 7Oct 10Oct 14Oct 16Oct 20Oct 24Oct 28Nov 3
28°FOct 15Oct 20Oct 24Oct 27Oct 31Nov 2Nov 5Nov 8Nov 14
24°FOct 28Nov 1Nov 5Nov 8Nov 10Nov 13Nov 17Nov 20Nov 26
20°FNov 5Nov 11Nov 14Nov 17Nov 21Nov 24Nov 28Dec 1Dec 6
16°FNov 13Nov 19Nov 23Nov 26Nov 30Dec 2Dec 5Dec 8Dec 14

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°F167161156152149146141137131
32°F191184178174169166162158152
28°F214208203199195191186181173
24°F235228224220217213210205199
20°F256249243240236231226222216
16°F271263258254250247242238231

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
7,385
Cooling degree days, base 65°F
329
Growing degree days, base 40°F
4,072
Growing degree days, base 45°F
3,047
Growing degree days, base 50°F
2,160
Growing degree days, base 55°F
1,399
Growing degree days, base 60°F
777

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,38700
February1,19000
March1,05902
April641136
May30113206
June8758422
July17130578
August3299532
September17927305
October513172
November81607
December1,16400

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 27.5 km from Warren 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 USC00301708 (Conklingville Dam). Public domain.