Bellport climate

Bellport Frost Dates and Growing Season

NOAA 1991-2020 normals for Shirley Brookhaven AP, 9.3 km from Bellport, elevation 82 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Shirley Brookhaven 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 18 and the first fall freeze around October 28, a growing season of about 193 days.

Median at 36°F
last April 30, first October 17
Median at 32°F
last April 18, first October 28
Median at 28°F
last April 3, first November 9

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 15May 9May 6May 3Apr 30Apr 27Apr 24Apr 22Apr 18
32°FMay 1Apr 26Apr 23Apr 21Apr 18Apr 16Apr 12Apr 9Apr 4
28°FApr 17Apr 13Apr 9Apr 6Apr 3Apr 1Mar 30Mar 26Mar 21
24°FApr 4Mar 31Mar 29Mar 26Mar 22Mar 19Mar 16Mar 12Mar 7
20°FMar 27Mar 21Mar 18Mar 15Mar 12Mar 9Mar 5Mar 1Feb 24
16°FMar 19Mar 13Mar 9Mar 5Mar 2Feb 27Feb 23Feb 16Feb 8

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 4Oct 7Oct 11Oct 13Oct 17Oct 20Oct 23Oct 27Nov 1
32°FOct 13Oct 17Oct 21Oct 25Oct 28Oct 31Nov 2Nov 5Nov 11
28°FOct 24Oct 31Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 25
24°FNov 5Nov 11Nov 15Nov 19Nov 22Nov 25Nov 29Dec 2Dec 7
20°FNov 18Nov 24Nov 29Dec 2Dec 5Dec 8Dec 13Dec 18Dec 24
16°FDec 1Dec 6Dec 11Dec 17Dec 20Dec 24Dec 29Jan 4Jan 12

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°F188182176172168164159155148
32°F211205200196193189185179172
28°F239231227222218214209204197
24°F266259254249245240235230221
20°F293285279274269264260254245
16°F317308303298292287281276266

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
5,346
Cooling degree days, base 65°F
784
Growing degree days, base 40°F
5,398
Growing degree days, base 45°F
4,142
Growing degree days, base 50°F
3,060
Growing degree days, base 55°F
2,149
Growing degree days, base 60°F
1,390

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03701
February90001
March798010
April493268
May22019271
June38130542
July2284747
August4247708
September6892474
October32411188
November591042
December87108

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 9.3 km from Bellport. 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 USW00054790 (Shirley Brookhaven AP). Public domain.