Old Greenwich — Water Temperature, Sea Conditions & Trends
This page provides clear and up-to-date information about water temperature for Old Greenwich (Connecticut, 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 Old Greenwich help you plan your visit and choose the best time for swimming.
Current Water Temperature
Water temperature in Old Greenwich 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 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming.
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 Old Greenwich 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 Old Greenwich will be 17.9°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 6 | 14.7°C | 16.3°C | |
| JUN 7 | 15.9°C | 16.5°C | |
| JUN 8 | 16.0°C | 16.0°C | |
| JUN 9 | 16.2°C | 17.0°C | |
| JUN 10 | 17.1°C | 16.8°C | |
| JUN 11 | 17.2°C | 17.3°C | |
| JUN 12 | 17.0°C | 17.8°C | |
| JUN 13 | 18.2°C | 18.0°C | |
| JUN 14 | 18.2°C | 18.0°C | 18.2°C |
| JUN 15 | 17.5°C | 18.2°C | |
| JUN 16 | 17.3°C | 18.1°C | |
| JUN 17 | 17.3°C | 18.1°C | |
| JUN 18 | 17.8°C | 18.0°C | |
| JUN 19 | 18.0°C | 18.0°C | |
| JUN 20 | 18.0°C | 18.0°C | |
| JUN 21 | 18.5°C | 17.9°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
Old Greenwich sits on the northern shore of Long Island Sound, and its coastal waters follow the Sound’s characteristic seasonal cycles. Water temperatures in winter typically hover near freezing up to about 6 °C, with the coldest months often between 0 °C and 4 °C. In spring the surface warms steadily, commonly ranging from roughly 6 °C in early spring to around 16 °C by late May. Summer brings the warmest conditions, with surface temperatures frequently between about 17 °C and 24 °C at the peak of July and August. During autumn the water cools again, moving from the mid-teens down toward single digits; typical fall values are approximately 8 °C to 18 °C depending on the month and recent weather patterns. These ranges can vary year to year with air temperature, currents and wind-driven mixing.
Monthly Water Temperature Range (Min, Max & Average)
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 2°C | 6°C | 8°C |
| February | 2°C | 4°C | 7°C |
| March | 2°C | 5°C | 8°C |
| April | 4°C | 8°C | 12°C |
| May | 8°C | 12°C | 18°C |
| June | 13°C | 17°C | 23°C |
| July | 18°C | 23°C | 26°C |
| August | 20°C | 23°C | 27°C |
| September | 18°C | 22°C | 25°C |
| October | 13°C | 19°C | 24°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.
Old Greenwich: Weather Forecast
June 15
June 16
June 17
June 18
Location, Beaches & Local Information
Nearby Beaches & Facilities
Uncas Point Beach
Greenwich Point Park
Fords Beach
John J. Boccuzzi Park
Greenwich Point Beach
Greenwich Point
Harbor Point Boardwalk
Harbor Point Beach
West Beach
Swimming Conditions
Swimming and beach recreation in Old Greenwich are largely shaped by these seasonal temperatures and by local amenities. The warmest and most comfortable swimming is usually confined to the high summer months when surface temperatures approach the low twenties °C; outside that period the water may feel brisk and is generally better suited for shorter dips, wetsuit use, or alternative activities. Public shoreline areas and nearby parks provide sandy stretches for sunbathing, family outings and launching small craft such as kayaks and paddleboards, while lifeguard coverage, restroom facilities and parking typically follow seasonal schedules. Visitors planning a beach-based holiday should check local opening times and services, arrive prepared for variable water conditions including tide and wind influence, and remember that early summer and late season outings will encounter significantly cooler water temperatures.