Block Island water temp
This data the coastal Block Island ocean 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 ocean temperature in Block Island
Water temperature in Block Island today is 49.3°F. Based on our historical data over a period of ten years, the warmest water in this day in the Atlantic Ocean near Block Island was recorded in 2015 and was 53.8°F, and the coldest was recorded in 2013 at 47.8°F. Sea water temperature in Block Island is expected to drop to 48.4°F in the next 10 days. December average water temperature in Block Island is 50.2°F, the minimum temperature is 43.7°F, and the maximum is 55.8°F.
The swimming season in Block Island lasts from July to September. During those months, Block Island water temperature does not drop below 68°F and therefore suitable for comfortable swimming. The average water temperature in Block Island in winter reaches 45.3°F, in spring 45.7°F, in summer the average temperature rises to 67.3°F, and in autumn it is 62.4°F.
Block Island water temperature now
| December 15, 2025 |
|---|
| today temp |
| 49.3°F |
| December 14, 2025 |
|---|
| yesterday temp |
| 49.8°F |
The ocean salinity in Block Island is 28.38‰, and the average salinity of the World Ocean is 35‰.
Surf Forecast in Block Island 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 Block Island. 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 Block Island. Data in table shown for December 16, 2025, time in GMT 0 format (you can change the time zone on the sea state forecast page)
| 0-3 h | 3-6 h | 6-9 h | 9-12 h |
|---|---|---|---|
| 4' 9" | 5' 1" | 5' 2" | 5' 2" |
| 1.46 m | 1.56 m | 1.58 m | 1.58 m |
| 12-15 h | 15-18 h | 18-21 h | 21-24 h |
|---|---|---|---|
| 4' 6" | 3' 11" | 4' 3" | 3' 10" |
| 1.38 m | 1.19 m | 1.29 m | 1.17 m |
Surf report in Block Island
Block Island weather forecast
Current temperature and weather
Data in a table show Block Island temperature today (December 16, 2025). For more information and forecast for a few days, go to the weather forecast Block Island.
| 0-3 h | 3-6 h | 6-9 h | 9-12 h |
|---|---|---|---|
 | | |  |
| 23°F | 18.9°F | 16.7°F | 20.5°F |
| 12-15 h | 15-18 h | 18-21 h | 21-24 h |
|---|---|---|---|
| |  |  |
| 28°F | 30.4°F | 31.5°F | 32.9°F |
You may also be interested in other sections of our site for Block Island: Sunrise and Sunset, Tides
Block Island water temperature by month
These figures shows the average, minimum and maximum monthly sea temperature in Block Island. 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 Block Island 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
| Month | Avr | Min | Max | |
|---|---|---|---|---|
| January | 44.6°F | 38.5°F | 50.5°F | cold |
| Ocean water temperature in Block Island in January | ||||
| February | 41°F | 34.9°F | 46.4°F | cold |
| Ocean water temperature in Block Island in February | ||||
| March | 41°F | 35.4°F | 50.4°F | cold |
| Ocean water temperature in Block Island in March | ||||
| April | 44.4°F | 37.8°F | 51.6°F | cold |
| Ocean water temperature in Block Island in April | ||||
| May | 51.8°F | 44.4°F | 63.9°F | cold |
| Ocean water temperature in Block Island in May | ||||
| June | 61.3°F | 53.2°F | 70.2°F | cold |
| Ocean water temperature in Block Island in June | ||||
| July | 69.6°F | 62.8°F | 74.7°F | warm |
| Ocean water temperature in Block Island in July | ||||
| August | 70.9°F | 66°F | 76.1°F | warm |
| Ocean water temperature in Block Island in August | ||||
| September | 67.8°F | 61.9°F | 74.7°F | cold |
| Ocean water temperature in Block Island in September | ||||
| October | 62.6°F | 55.6°F | 68.2°F | cold |
| Ocean water temperature in Block Island in October | ||||
| November | 56.7°F | 51.1°F | 62.4°F | cold |
| Ocean water temperature in Block Island in November | ||||
| December | 50.2°F | 43.7°F | 55.8°F | cold |
| Ocean water temperature in Block Island in December | ||||
Chart monthly average water temperature in Block Island
