Water Mill climate

Water Mill Frost Dates and Growing Season

NOAA 1991-2020 normals for Bridgehampton, 5.2 km from Water Mill, elevation 42 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bridgehampton. 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 23 and the first fall freeze around October 24, a growing season of about 182 days.

Median at 36°F
last May 6, first October 12
Median at 32°F
last April 23, first October 24
Median at 28°F
last April 8, first November 5

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 15May 11May 9May 6May 3Apr 30Apr 28Apr 24
32°FMay 8May 3Apr 30Apr 26Apr 23Apr 20Apr 18Apr 15Apr 11
28°FApr 24Apr 18Apr 15Apr 11Apr 8Apr 6Apr 4Apr 1Mar 28
24°FApr 7Apr 3Apr 1Mar 30Mar 28Mar 24Mar 20Mar 16Mar 9
20°FMar 29Mar 25Mar 20Mar 17Mar 14Mar 11Mar 7Mar 3Feb 27
16°FMar 19Mar 14Mar 10Mar 6Mar 3Mar 1Feb 25Feb 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°FOct 2Oct 5Oct 8Oct 10Oct 12Oct 15Oct 18Oct 21Oct 26
32°FOct 11Oct 15Oct 18Oct 21Oct 24Oct 27Oct 30Nov 2Nov 7
28°FOct 22Oct 27Oct 30Nov 1Nov 5Nov 8Nov 12Nov 16Nov 22
24°FNov 1Nov 7Nov 11Nov 15Nov 18Nov 21Nov 25Nov 30Dec 5
20°FNov 15Nov 21Nov 25Nov 29Dec 2Dec 5Dec 8Dec 13Dec 20
16°FDec 1Dec 4Dec 8Dec 13Dec 16Dec 20Dec 25Dec 31Jan 6

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°F178172167162159155151146140
32°F202195190185182178175170162
28°F230222217212209205201195187
24°F259251246241236232228223216
20°F287278273268263259254248240
16°F311304298292288283278272264

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
5,704
Cooling degree days, base 65°F
576
Growing degree days, base 40°F
4,913
Growing degree days, base 45°F
3,705
Growing degree days, base 50°F
2,678
Growing degree days, base 55°F
1,821
Growing degree days, base 60°F
1,121

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,06201
February93400
March84605
April550139
May2808208
June6286474
July5223683
August8190646
September8763427
October3566156
November621034
December89405

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 5.2 km from Water Mill. 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 USC00300889 (Bridgehampton). Public domain.