All data are in degrees Fahrenheit

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Water temperature in South Boston

Detailed information about the current water temperature in South Boston. The trend over the last two weeks, daily averages, and precise forecast of the water temperature changes. Gain a deeper understanding of seasonal dynamics with monthly statistical analyses covering recent years.
Sea temperature in South Boston now

41.8

°F

December 25, 05:17

Trend:

increasing

Yesterday:

41.5°F

Tomorrow:

42.0°F

Sunrise:

07:12

Sunset:

16:17

Day Length:

9 h. 5 min.

South Boston in January

Minimum:

40.0°F

Average:

42.3°F

Maximum:

46.1°F

Sea water temperature in South Boston today

As of now, in South Boston, the water temperature is 41.8°F. Swimming in water of this temperature is considered as extremely cold, and there's a substantial risk of hypothermia if exposed for more than a brief duration. Today's reading is 0.9°F lower than the average recorded on this particular day in recent years. Since yesterday, there was a slight increase in temperature. This indicates a warming trend over the past day. According to the forecast, we expect the temperature to rise a bit.

Recent sea temperature and forecast

Today's water temperature is slightly lower than the average registered over the last two weeks, indicating a slight cooling trend. It also aligns closely with the historical average temperature for this date, indicating a typical climate pattern. The maximum temperature recorded for this date was 47.8°F on 2015, while the historical minimum was 39.6°F on 2019.

Observations from the last two weeks indicate that the water temperature was in proximity to the lowest values recorded on those days in the past. Over the next week, the forecast shows a steady trend, with temperatures staying close to the average of 41.7°F. Both minimum and maximum temperatures expected to be close to the average, offering a week of stable water conditions.

Daily water temperature in South Boston

Date Current Year

actual* / forecast**

last year 10 years average
Jan 1 41.4°F 40.0°F 42.3°F
Dec 11 44.2°F 44.2°F 45.5°F
Dec 12 43.6°F 44.4°F 45.4°F
Dec 13 43.3°F 43.9°F 45.2°F
Dec 14 43.4°F 42.2°F 44.7°F
Dec 15 43.4°F 41.0°F 44.5°F
Dec 16 42.4°F 41.7°F 44.2°F
Dec 17 42.5°F 42.3°F 44.2°F
Dec 18 42.0°F 42.9°F 44.3°F
Dec 19 40.9°F 42.4°F 44.0°F
Dec 20 41.4°F 42.7°F 43.6°F
Dec 21 41.1°F 42.8°F 43.3°F
Dec 22 41.2°F 41.9°F 43.4°F
Dec 23 41.2°F 41.1°F 43.1°F
Dec 24 41.5°F 41.4°F 42.8°F
Dec 25 41.8°F 41.2°F 42.7°F
Dec 26 42.0°F 41.4°F 42.9°F
Dec 27 41.9°F 41.1°F 42.9°F
Dec 28 42.0°F 41.4°F 42.9°F
Dec 29 41.8°F 41.5°F 42.7°F
Dec 30 41.5°F 41.7°F 42.5°F
Dec 31 41.3°F 39.4°F 42.3°F

* actual - actual temperature values

** forecast - projected values for the next week

Real-time coastal temperatures could deviate by several degrees from the provided readings. These deviations often become evident following intense rainfall or strong winds.

Our forecasting methodology leverages a mathematical model, that uses current water and weather conditions, historical records, wind intensity and direction.

Sea water temperature in South Boston by month

In an average year, South Boston offers no days when the water temperature is warm enough to swim comfortably.
The warmest water in South Boston was recorded on July 29, 2020, reaching a 75.0°F. While the coldest temperature occurred on February 11, 2025, dipping to 32.5°F. The average readings by season are 41.0°F in Winter, 45.1°F in Spring, 65.0°F in Summer, and 58.0°F in Autumn.

Popular neighboring cities and resorts

City Water temperature* Distance**
Boston 41.8°F 2mi
Salem 43.0°F 15mi
Plymouth 41.1°F 32mi
Providence 38.7°F 40mi
Bristol 37.9°F 47mi

* current water temperature in this city

** straight line distance from South Boston