Bellport — Water Temperature, Sea Conditions & Trends

Water Temperature: Daily Trends, Historical Records, and Forecast

⚠️ As of today, the minimum water temperature ranges from 60°F (15°C) to 65°F (18°C). The water is comfortable for most people, making it an ideal range for water sports enthusiasts. The temperature does not cause significant discomfort, and swimming will be pleasant for the majority. However, it's important to remember that prolonged exposure to the water can still lead to cooling, so it's essential to monitor the time spent in the water, especially for children or elderly people.

It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.

Water Temperature Chart Over the Last 30 Days

Water temperature in Bellport has risen over the last week and month. Currently, the sea water temperature at this location matches the average for this day in previous years.

According to our forecast, Water temperature in Bellport will be 18.3°C in the next 7 days. See the table below for daily data for the upcoming week.

Table of Daily Sea Temperature Data

Annual Water Temperature Overview by Month

Monthly Water Temp Ranges

30°C

25°C

20°C

15°C

10°c

5°C

0°C

Annual Water Temperature Trend

Bellport is a small village on Long Island’s south shore, fronting the sheltered waters of the Great South Bay. Because the bay is relatively shallow and protected from open-ocean swell, its water temperature follows clear seasonal patterns but can change quickly with weather and tidal flow. Typical winter temperatures from December through February range from about 0°C to 5°C, often too cold for casual swimming. In spring, March through May, waters usually rise into the 5°C–15°C band as air temperatures and sunlight increase. Summer months, June to August, are when the bay is warmest, commonly reaching about 18°C–25°C at peak, with the warmest readings in July and August. In autumn, September to November, temperatures gradually fall, often sitting between roughly 10°C and 20°C before the onset of winter chill. Local conditions such as recent storms, wind direction, or runoff can shift these values by several degrees.