Port Jefferson water temp

This data the coastal Port Jefferson sea water temperature today, tomorrow and the upcoming days. Besides, you can also get information about the weather and surf forecast, as well as the data on sunrise / sunset and moonrise / moonset at a given point on any given day.

Current sea temperature in Port Jefferson

Water temperature in Port Jefferson today is 70.2°F. Based on our historical data over a period of ten years, the warmest water in this day in the Long Island Sound near Port Jefferson was recorded in 2018 and was 73°F, and the coldest was recorded in 2009 at 67.3°F. Sea water temperature in Port Jefferson is expected to drop to 69.3°F in the next 10 days. September average water temperature in Port Jefferson is 71.6°F, the minimum temperature is 66.9°F, and the maximum is 77.5°F.

The swimming season in Port Jefferson lasts from July to September. During those months, Port Jefferson water temperature does not drop below 68°F and therefore suitable for comfortable swimming. The average water temperature in Port Jefferson in winter reaches 41.2°F, in spring 45.7°F, in summer the average temperature rises to 70°F, and in autumn it is 64.2°F.

Port Jefferson water temperature now

The sea salinity in Port Jefferson is 27.82‰, and the average salinity of the World Ocean is 35‰.

Surf Forecast in Port Jefferson for today

Another important indicators for a comfortable holiday on the beach are the presence and height of the waves, as well as the speed and direction of the wind. Please find below data on the swell size for Port Jefferson. We calculate the swell size based on the mean wave height (trough to crest) of each third highest wave. For more information on surf forecasts for the next ten days, please visit sea state forecast Port Jefferson. Data in table shown for September 20, 2025, time in GMT 0 format (you can change the time zone on the sea state forecast page)

Surf report in Port Jefferson

Port Jefferson weather forecast

Current temperature and weather

Data in a table show Port Jefferson temperature today (September 20, 2025). For more information and forecast for a few days, go to the weather forecast Port Jefferson.

0-3 h	3-6 h	6-9 h	9-12 h
68.2°F	64.2°F	61.5°F	62.2°F

12-15 h	15-18 h	18-21 h	21-24 h
66.6°F	69.3°F	67.5°F	63.9°F

Port Jefferson water temperature by month

These figures shows the average, minimum and maximum monthly sea temperature in Port Jefferson. In addition to the table values, the graph below displays of changes average surface temperature during the year. Values are calculated based on the data over the past 10 years. Using them, you can check the water temperature in Port Jefferson on any day of this period that interests you. Click on the month link and you will see a table for each day, or alternatively you can view the temperature curve of the month and select 2 different years you want to compare, either in a table or as a curve

Chart monthly average water temperature in Port Jefferson

The nearest beaches and cities from Port Jefferson with the water temperature today, as well as the air temperature and the state of the weather during the day and the average wave height for today

	Water	Weather		Wave
New York City	71.6°F	69.8°F		1' 0"
Flax Pond Beach	70.9°F	69.8°F		1' 2"
Cedar Beach Mt Sinai	70.7°F	69.8°F		1' 2"
Stony Brook	71.1°F	69.8°F		1' 2"
Sunken Meadow	71.2°F	68°F		1' 1"
Smithtown	71.2°F	68°F		1' 1"
West Meadow Beach	71.2°F	68°F		1' 1"
Short Beach	71.2°F	68°F		1' 1"
Stratford	71.1°F	68°F		1' 3"
Short Beach	71.1°F	68°F		1' 3"

If you have interesting photos of this place, you can upload them here. Photos will be available to all users after verification by the moderator.

Port Jefferson Harbor

Get widget or API for your website

Our report for Port Jefferson is compiled using satellite data together with in-situ observations to get the most reliable daily data of sea surface temperatures, surf forecasts, current temperatures and weather forecasts.