Patchogue climate

Patchogue Frost Dates and Growing Season

NOAA 1991-2020 normals for Islip Li Macarthur AP, 7.9 km from Patchogue, elevation 84 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Islip Li Macarthur AP. 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 10 and the first fall freeze around November 2, a growing season of about 207 days.

Median at 36°F
last April 23, first October 21
Median at 32°F
last April 10, first November 2
Median at 28°F
last March 30, first November 14

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 7May 2Apr 29Apr 26Apr 23Apr 20Apr 18Apr 14Apr 11
32°FApr 25Apr 20Apr 16Apr 13Apr 10Apr 7Apr 5Apr 3Mar 31
28°FApr 12Apr 6Apr 3Mar 31Mar 30Mar 28Mar 25Mar 20Mar 14
24°FMar 31Mar 28Mar 24Mar 20Mar 17Mar 14Mar 11Mar 7Mar 1
20°FMar 22Mar 17Mar 14Mar 10Mar 7Mar 4Mar 1Feb 26Feb 19
16°FMar 14Mar 8Mar 4Feb 28Feb 25Feb 20Feb 15Feb 11Feb 3

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 8Oct 12Oct 16Oct 19Oct 21Oct 24Oct 28Oct 31Nov 4
32°FOct 18Oct 24Oct 28Oct 31Nov 2Nov 4Nov 7Nov 11Nov 15
28°FNov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 20Nov 25Dec 1
24°FNov 11Nov 15Nov 19Nov 23Nov 27Dec 1Dec 3Dec 7Dec 12
20°FNov 23Nov 30Dec 3Dec 7Dec 10Dec 13Dec 18Dec 24Dec 31
16°FDec 6Dec 12Dec 19Dec 23Dec 28Jan 1Jan 6Jan 11Jan 20

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°F199194189185182178174169162
32°F223218214210207203199195188
28°F250243238233230226222217211
24°F275267261257253249244238231
20°F301293287282277272267261254
16°F326318312306303299294288279

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
5,183
Cooling degree days, base 65°F
885
Growing degree days, base 40°F
5,618
Growing degree days, base 45°F
4,346
Growing degree days, base 50°F
3,242
Growing degree days, base 55°F
2,303
Growing degree days, base 60°F
1,518

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02602
February88901
March780012
April460382
May19627300
June30152572
July1312776
August2271735
September53108506
October30113205
November582045
December86508

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 7.9 km from Patchogue. 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 USW00004781 (Islip Li Macarthur AP). Public domain.