All data are in degrees Fahrenheit

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Water temperature in Isumi

Detailed information about the current water temperature in Isumi. 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 Isumi now

60.6

°F

January 29, 16:38

Trend:

increasing

Yesterday:

60.5°F

Tomorrow:

60.9°F

Sunrise:

06:40

Sunset:

17:03

Day Length:

10 h. 23 min.

Isumi in February

Minimum:

58.6°F

Average:

63.1°F

Maximum:

66.0°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 60.6°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 0.4°F lower than the average recorded on this particular day in recent years. The sea temperature remains approximately unchanged from yesterday. According to the forecast, we expect the temperature to rise a bit.

Recent sea temperature and forecast

Today's water temperature closely matches the previous two weeks' average, indicating a stable trend. It also falls within the range of the average temperature recorded for this date, suggesting a consistent weather trend. The maximum temperature recorded for this date was 64.2°F on 2017, while the historical minimum was 57.9°F on 2019.

The water temperature over the last two weeks displayed soome variability. While the two week average stayed close to the historical average, there were some days when the temperature was close to the histoorical minimum and others when it was close to the historical maximum. The forecast for the upcoming week shows a gradual cooling trend. The average temperature is expected to be 59.9°F, the minimum temperature may reach 59.6°F, and the maximum might stay at 60.9°F.

Daily water temperature in Isumi

Date Current Year

actual* / forecast**

last year 10 years average
Jan 15 58.5°F 62.4°F 61.1°F
Jan 16 57.2°F 61.7°F 60.8°F
Jan 17 58.1°F 60.3°F 60.9°F
Jan 18 60.7°F 58.3°F 61.1°F
Jan 19 60.9°F 59.2°F 60.9°F
Jan 20 62.7°F 59.4°F 61.0°F
Jan 21 62.2°F 59.9°F 60.8°F
Jan 22 62.2°F 57.9°F 60.7°F
Jan 23 62.6°F 59.6°F 60.8°F
Jan 24 62.0°F 59.7°F 60.7°F
Jan 25 60.7°F 60.8°F 60.2°F
Jan 26 61.0°F 59.1°F 60.5°F
Jan 27 61.1°F 58.3°F 60.5°F
Jan 28 60.5°F 62.6°F 60.9°F
Jan 29 60.6°F 62.5°F 61.0°F
Jan 30 60.9°F 60.0°F 61.3°F
Jan 31 60.0°F 59.1°F 60.4°F
Feb 1 59.9°F 58.7°F 60.3°F
Feb 2 59.8°F 58.9°F 60.2°F
Feb 3 59.6°F 58.7°F 60.0°F
Feb 4 59.6°F 58.6°F 60.0°F
Feb 5 59.9°F 61.2°F 60.3°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 Isumi by month

In Isumi, the months July through October offer comfortable swimming conditions, which amounts to 109 swimming days.
The warmest water in Isumi was recorded on August 17, 2024, reaching a 82.8°F. While the coldest temperature occurred on April 20, 2025, dipping to 53.1°F. The average readings by season are 62.1°F in Winter, 61.8°F in Spring, 74.2°F in Summer, and 74.0°F in Autumn.

Popular neighboring cities and resorts

City Water temperature* Distance**
Katsuura 61.9°F 8mi
Ichihara 50.1°F 27mi
Kisarazu 51.3°F 29mi
Chiba 49.2°F 30mi
Kimitsu 51.7°F 31mi
Futtsu 53.2°F 34mi
Honchō 48.2°F 40mi
Yokosuka 55.9°F 42mi
Kawasaki 51.4°F 44mi
Yokohama 54.1°F 45mi

* current water temperature in this city

** straight line distance from Isumi