Brookhaven climate

Brookhaven Frost Dates and Growing Season

NOAA 1991-2020 normals for Brookhaven City, 4.1 km from Brookhaven, elevation 435 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Brookhaven City. 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 March 17 and the first fall freeze around November 12, a growing season of about 242 days.

Median at 36°F
last April 1, first November 3
Median at 32°F
last March 17, first November 12
Median at 28°F
last March 1, first November 28

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°FApr 20Apr 12Apr 8Apr 5Apr 1Mar 29Mar 24Mar 18Mar 11
32°FApr 7Apr 1Mar 27Mar 22Mar 17Mar 12Mar 7Mar 1Feb 22
28°FMar 23Mar 15Mar 10Mar 6Mar 1Feb 26Feb 20Feb 12Jan 31
24°FMar 11Mar 3Feb 26Feb 19Feb 11Feb 3Jan 30Jan 23Jan 12
20°FFeb 28Feb 16Feb 6Feb 1Jan 28Jan 22Jan 13Jan 5Dec 26
16°FFeb 10Feb 2Jan 29Jan 24Jan 18Jan 12Jan 7Jan 2Dec 27

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 19Oct 24Oct 28Nov 1Nov 3Nov 5Nov 8Nov 12Nov 18
32°FOct 26Nov 1Nov 5Nov 8Nov 12Nov 16Nov 20Nov 26Dec 2
28°FNov 6Nov 12Nov 17Nov 23Nov 28Dec 1Dec 6Dec 13Dec 31
24°FNov 20Nov 30Dec 3Dec 9Dec 20Dec 28Jan 1Jan 9Jan 22
20°FDec 3Dec 12Dec 24Dec 31Jan 3Jan 8Jan 13Jan 20Feb 3
16°FDec 21Dec 30Jan 1Jan 6Jan 9Jan 13Jan 18Jan 27Feb 1

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°F242233227221216211207201193
32°F270261253248242235230222212
28°F310296286277271264257249239
24°F349334326318308298290282269
20°F365365364352343334328318303
16°F365365365365365365362348335

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
97% of years
20°F or colder
73% of years
16°F or colder
33% 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
2,300
Cooling degree days, base 65°F
2,122
Growing degree days, base 40°F
9,047
Growing degree days, base 45°F
7,374
Growing degree days, base 50°F
5,828
Growing degree days, base 55°F
4,427
Growing degree days, base 60°F
3,185

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January572483
February4107119
March26526264
April11474415
May18224671
June0391841
July0473938
August0471936
September5322768
October96107480
November31616202
December5057111

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 4.1 km from Brookhaven. 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 USC00221094 (Brookhaven City). Public domain.