Caldwell climate

Caldwell Frost Dates and Growing Season

NOAA 1991-2020 normals for Essex Fells Service Bldg, 1.3 km from Caldwell, elevation 350 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Essex Fells Service Bldg. 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 18 and the first fall freeze around October 24, a growing season of about 187 days.

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

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 3Oct 5Oct 8Oct 11Oct 14Oct 17Oct 21Oct 26
32°FOct 8Oct 14Oct 17Oct 21Oct 24Oct 27Oct 30Nov 2Nov 6
28°FOct 21Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 14Nov 20
24°FNov 1Nov 6Nov 11Nov 14Nov 18Nov 22Nov 26Dec 1Dec 6
20°FNov 15Nov 20Nov 26Nov 30Dec 3Dec 6Dec 12Dec 18Dec 25
16°FNov 29Dec 3Dec 10Dec 14Dec 19Dec 23Dec 28Jan 2Jan 9

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°F182176171165161157153149142
32°F207201196191187182177171164
28°F236226221216212208204198190
24°F264255249244239235229224216
20°F289280274269264259254249241
16°F313305298294289284279271262

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
5,437
Cooling degree days, base 65°F
908
Growing degree days, base 40°F
5,559
Growing degree days, base 45°F
4,327
Growing degree days, base 50°F
3,247
Growing degree days, base 55°F
2,315
Growing degree days, base 60°F
1,534

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08902
February93102
March788018
April4228121
May17842332
June31170589
July1308772
August4262724
September79106478
October35412169
November639035
December92106

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 1.3 km from Caldwell. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00282768 (Essex Fells Service Bldg). Public domain.