What is the current water temperature in Isumi?

As of now, in Isumi, the water temperature is 23.42°C. It's safe to say that the water is comfortably warm for various water-related activities.

Japan > Isumi

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.

74.2

°F

October 27, 22:40

Trend:

stable

Yesterday:

74.4°F

Tomorrow:

74.5°F

Sunrise:

05:54

Sunset:

16:50

Day Length:

10 h. 56 min.

Isumi in November

Minimum:

58.4°F

Average:

62.5°F

Maximum:

64.7°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 74.2°F. It's safe to say that the water is comfortably warm for various water-related activities. Today's reading is 1.2°F higher 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 76.6°F on 2024, while the historical minimum was 71.3°F on 2017.

latest data

last year

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 73.5°F, the minimum temperature may reach 72.9°F, and the maximum might stay at 74.5°F.

Daily water temperature in Isumi

Date	Current Year actual* / forecast**	last year	10 years average
Oct 13	74.6°F	75.9°F	75.1°F
Oct 14	72.2°F	75.0°F	74.5°F
Oct 15	72.4°F	75.2°F	74.6°F
Oct 16	72.5°F	75.3°F	74.4°F
Oct 17	74.7°F	77.0°F	74.7°F
Oct 18	73.5°F	76.5°F	74.5°F
Oct 19	73.5°F	77.6°F	74.5°F
Oct 20	75.3°F	77.0°F	74.2°F
Oct 21	75.7°F	76.5°F	74.2°F
Oct 22	75.1°F	76.0°F	74.2°F
Oct 23	74.9°F	75.6°F	73.9°F
Oct 24	74.8°F	76.4°F	73.8°F
Oct 25	74.7°F	76.2°F	73.8°F
Oct 26	74.4°F	75.8°F	73.3°F
Oct 27	74.2°F	74.0°F	73.0°F
Oct 28	74.5°F	75.6°F	73.3°F
Oct 29	74.0°F	75.2°F	72.8°F
Oct 30	73.6°F	74.0°F	72.4°F
Oct 31	73.1°F	73.7°F	71.9°F
Nov 1	73.2°F	72.9°F	72.0°F
Nov 2	73.1°F	71.5°F	71.9°F
Nov 3	72.9°F	71.3°F	71.7°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, 74.3°F in Summer, and 74.0°F in Autumn.

Popular neighboring cities and resorts

City	Water temperature*	Distance**
Katsuura	75.7°F	8mi
Ichihara	72.2°F	27mi
Kisarazu	72.6°F	29mi
Chiba	72.2°F	30mi
Kimitsu	72.7°F	31mi
Futtsu	73.1°F	34mi
Honchō	72.4°F	40mi
Yokosuka	73.8°F	42mi
Kawasaki	73.1°F	44mi
Yokohama	73.6°F	45mi

* current water temperature in this city

** straight line distance from Isumi