Long Island — Water Temperature, Sea Conditions & Trends
This page provides clear and up-to-date information about water temperature for Long Island (New York, United States). It includes the current water temperature, daily data for the last month presented in a simple chart, and a 7-day forecast. The page also compares today’s value with typical averages for this period, shows usual monthly ranges during the year, and lists nearby beaches with short descriptions. Local weather for the next few days and general details about Long Island help you plan your visit and choose the best time for swimming.
Current Water Temperature
Water temperature in Long Island in the Atlantic Ocean today is 18°C.
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 Long Island 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 Long Island will be 17.6°C in the next 7 days. See the table below for daily data for the upcoming week.
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| JUN 2 | 14.3°C | 14.0°C | |
| JUN 3 | 14.0°C | 13.8°C | |
| JUN 4 | 13.7°C | 14.8°C | |
| JUN 5 | 14.1°C | 14.8°C | |
| JUN 6 | 14.5°C | 15.3°C | |
| JUN 7 | 15.3°C | 16.0°C | |
| JUN 8 | 16.0°C | 16.5°C | |
| JUN 9 | 16.7°C | 16.5°C | |
| JUN 10 | 17.5°C | 16.5°C | 17.5°C |
| JUN 11 | 16.5°C | 17.5°C | |
| JUN 12 | 16.5°C | 17.5°C | |
| JUN 13 | 17.0°C | 17.6°C | |
| JUN 14 | 17.3°C | 17.6°C | |
| JUN 15 | 17.3°C | 17.6°C | |
| JUN 16 | 17.3°C | 17.6°C | |
| JUN 17 | 17.5°C | 17.6°C |
* Current - Actual water temperature value
** Average - Average water temperature on this day in recent years
*** Forecast - Our water temperature forecast
Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.
Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.
Water temperature data for this location is gathered from various sources, including buoys and satellite sea and ocean surface maps provided by the NOAA agency. We also incorporate data from local authorities in each specific location worldwide to ensure more accurate temperature readings.
Annual Water Temperature Overview by Month
Monthly Water Temp Ranges
Annual Water Temperature Trend
Long Island’s coastline spans a variety of marine environments, from the open Atlantic on the south shore to the more sheltered waters of Long Island Sound, Great South Bay and Peconic Bay. Water temperatures vary with season, location and tidal influence, and can differ by several degrees between bays and the open ocean. Typical seasonal ranges are roughly 0–6°C in winter when the water is near freezing, rising in spring to about 5–15°C as warming begins, peaking in summer around 18–24°C in July and August in most spots, and then cooling in autumn to approximately 10–18°C. Shallow bays and protected inlets tend to warm faster and reach higher temperatures in summer than the exposed ocean beaches, while eastern reaches near Montauk can remain slightly cooler or be influenced by offshore currents.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 2°C | 6°C | 9°C |
| February | 2°C | 4°C | 7°C |
| March | 2°C | 5°C | 7°C |
| April | 4°C | 8°C | 12°C |
| May | 8°C | 12°C | 17°C |
| June | 13°C | 18°C | 23°C |
| July | 18°C | 23°C | 26°C |
| August | 21°C | 23°C | 26°C |
| September | 18°C | 21°C | 25°C |
| October | 13°C | 18°C | 23°C |
| November | 9°C | 14°C | 18°C |
| December | 5°C | 9°C | 13°C |
* Click on a month to view detailed water temperature data.
Long Island: Weather Forecast
June 10
June 11
June 12
Location, Beaches & Local Information
Nearby Beaches & Facilities
Sayville Marina Park
Sayville Beach
Bayport Beach
Swimming Conditions
Swimming and beach holidays on Long Island are highly seasonal, with the safest and most comfortable conditions in mid to late summer when lifeguards are on duty and water temperatures are warmest. Sheltered bay beaches are popular with families for shallower, warmer water, whereas the south shore offers surf, surfing opportunities and wider sandy stretches that can have stronger currents and bigger waves. Shoulder seasons can be pleasant for shoreline walks and limited dips, but many visitors use wetsuits or restrict swimming then because water temperatures can be brisk. As with any coastal destination, swimmers should heed local advisories about water quality, rip currents and jellyfish, and choose monitored beaches for safer swimming and full holiday amenities.