Great Bay water temp
This data the coastal Great Bay 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 Great Bay
Water temperature in Great Bay today is 71.4°F. Based on our historical data over a period of ten years, the warmest water in this day in the Atlantic Ocean near Great Bay was recorded in 2019 and was 71.8°F, and the coldest was recorded in 2023 at 65.7°F. Sea water temperature in Great Bay is expected to drop to 66.6°F in the next 10 days. October average water temperature in Great Bay is 64.9°F, the minimum temperature is 57°F, and the maximum is 73.2°F.
The swimming season in Great Bay lasts from June to September. During those months, Great Bay water temperature does not drop below 68°F and therefore suitable for comfortable swimming. The average water temperature in Great Bay in winter reaches 42.8°F, in spring 49.5°F, in summer the average temperature rises to 72.9°F, and in autumn it is 64.2°F.
Great Bay water temperature now
| October 1, 2025 |
|---|
| today temp |
| 71.4°F |
| September 30, 2025 |
|---|
| yesterday temp |
| 72.1°F |
The ocean salinity in Great Bay is 29.78‰, and the average salinity of the World Ocean is 35‰.
Surf Forecast in Great Bay 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 Great Bay. 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 Great Bay. Data in table shown for October 1, 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 |
|---|---|---|---|
| 7' 4" | 7' 11" | 8' 5" | 8' 7" |
| 2.23 m | 2.42 m | 2.56 m | 2.62 m |
| 12-15 h | 15-18 h | 18-21 h | 21-24 h |
|---|---|---|---|
| 8' 8" | 8' 2" | 7' 9" | 7' 4" |
| 2.64 m | 2.5 m | 2.35 m | 2.24 m |
Surf report in Great Bay
Great Bay weather forecast
Current temperature and weather
Data in a table show Great Bay temperature today (October 1, 2025). For more information and forecast for a few days, go to the weather forecast Great Bay.
| 0-3 h | 3-6 h | 6-9 h | 9-12 h |
|---|---|---|---|
 | | |  |
| 68.4°F | 67.1°F | 65.1°F | 64.4°F |
| 12-15 h | 15-18 h | 18-21 h | 21-24 h |
|---|---|---|---|
 | | |  |
| 64.6°F | 67.8°F | 69.1°F | 64.8°F |
You may also be interested in other sections of our site for Great Bay: Sunrise and Sunset, Tides
Great Bay water temperature by month
These figures shows the average, minimum and maximum monthly sea temperature in Great Bay. 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 Great Bay 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 | 41.7°F | 33.1°F | 50°F | cold |
| Ocean water temperature in Great Bay in January | ||||
| February | 39.7°F | 32.5°F | 45.9°F | cold |
| Ocean water temperature in Great Bay in February | ||||
| March | 42.4°F | 33.3°F | 51.3°F | cold |
| Ocean water temperature in Great Bay in March | ||||
| April | 48.7°F | 40.6°F | 58.6°F | cold |
| Ocean water temperature in Great Bay in April | ||||
| May | 57.4°F | 48.9°F | 68.5°F | cold |
| Ocean water temperature in Great Bay in May | ||||
| June | 67.8°F | 59.4°F | 76.6°F | cold |
| Ocean water temperature in Great Bay in June | ||||
| July | 75.2°F | 67.5°F | 83.1°F | warm |
| Ocean water temperature in Great Bay in July | ||||
| August | 75.6°F | 69.8°F | 80.2°F | warm |
| Ocean water temperature in Great Bay in August | ||||
| September | 72.1°F | 66.6°F | 80.4°F | warm |
| Ocean water temperature in Great Bay in September | ||||
| October | 64.9°F | 57°F | 73.2°F | cold |
| Ocean water temperature in Great Bay in October | ||||
| November | 55.4°F | 46.9°F | 63.5°F | cold |
| Ocean water temperature in Great Bay in November | ||||
| December | 46.9°F | 36.7°F | 54.1°F | cold |
| Ocean water temperature in Great Bay in December | ||||
Chart monthly average water temperature in Great Bay
