Harman US

Port Jefferson, NY Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Port Jefferson, a village in Suffolk County, New York.

This Afternoon
68°F
Mostly Sunny
Mostly sunny. High near 68, with temperatures falling to around 66 in the afternoon. East wind around 8 mph.

7-day forecast for Port Jefferson

WhenTempForecastWindPrecip
This Afternoon 68°F Mostly Sunny 8 mph E 0%
Tonight 57°F Mostly Cloudy 7 mph SE 2%
Sunday 71°F Rain Showers then Rain 6 to 12 mph SE 84%
Sunday Night 57°F Rain then Rain Showers 7 to 14 mph W 84%
Monday 68°F Chance Rain Showers 9 to 15 mph NE 36%
Monday Night 55°F Chance Rain Showers 9 to 14 mph NE 26%
Tuesday 65°F Chance Rain Showers 15 mph NE 26%
Tuesday Night 54°F Slight Chance Rain Showers then Mostly Cloudy 14 to 17 mph NE 23%
Wednesday 66°F Mostly Cloudy 17 to 21 mph NE 12%
Wednesday Night 54°F Slight Chance Rain Showers 20 mph NE 23%
Thursday 65°F Chance Rain Showers 21 mph NE 33%
Thursday Night 53°F Chance Rain Showers 21 mph NE 39%
Friday 65°F Chance Rain Showers 23 mph N 43%
Friday Night 54°F Chance Rain Showers 20 to 23 mph N 43%

Forecast source: National Weather Service (api.weather.gov) for Port Jefferson (40.942, -73.053). Updated through the day.

Growing snapshot for Port Jefferson

Last spring frost
Apr 15
First fall frost
Nov 10
Growing season
208 days
Hardiness zone
7b

More local growing data for Port Jefferson: nearby ZIP 11777 weather · frost dates · planting calendar · New York frost dates

Nearby towns & communities

All New York locations ›

Climate data from the nearest NOAA station, Setauket Strong, Ny (2 mi from Port Jefferson). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.