What is the current water temperature in Isumi?

Q: What is the current water temperature in Isumi?

As of now, in Isumi, the water temperature is 16.69°C. Swimming in water of this temperature is generally concidered to be cool, and most people won't really enjoy it.

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.

62.0

°F

February 5, 17:50

Trend:

stable

Yesterday:

61.3°F

Tomorrow:

61.6°F

Sunrise:

06:35

Sunset:

17:10

Day Length:

10 h. 35 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 62.0°F. Swimming in water of this temperature is generally concidered to be cool, and most people won't really enjoy it. Today's reading is 1.8°F higher 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 fall a bit.

Recent sea temperature and forecast

The water temperature today is above average for the last two weeks, showing a small increase in temperature. It is also close to the historical maximum temperature for this date. The maximum temperature recorded for this date was 62.8°F on 2017, while the historical minimum was 58.7°F on 2019.

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 maximum recorded over the past years. The forecast for the upcoming week shows a gradual cooling trend. The average temperature is expected to be 61.4°F, the minimum temperature may reach 61.0°F, and the maximum might stay at 62.0°F.

Daily water temperature in Isumi

Date	Current Year actual* / forecast**	last year	10 years average
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	60.8°F
Jan 29	61.1°F	62.5°F	61.0°F
Jan 30	60.2°F	60.0°F	61.2°F
Jan 31	61.2°F	59.1°F	60.4°F
Feb 1	61.6°F	58.7°F	60.4°F
Feb 2	61.3°F	58.9°F	60.3°F
Feb 3	61.7°F	58.7°F	60.2°F
Feb 4	61.3°F	58.6°F	60.1°F
Feb 5	62.0°F	61.2°F	60.3°F
Feb 6	61.6°F	60.8°F	59.9°F
Feb 7	61.4°F	59.8°F	59.6°F
Feb 8	61.0°F	57.3°F	59.2°F
Feb 9	61.4°F	57.4°F	59.6°F
Feb 10	61.3°F	57.2°F	59.5°F
Feb 11	61.5°F	58.4°F	59.7°F
Feb 12	62.0°F	58.1°F	60.2°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	62.9°F	8mi
Ichihara	51.4°F	27mi
Kisarazu	54.8°F	29mi
Chiba	50.6°F	30mi
Kimitsu	55.3°F	31mi
Futtsu	57.1°F	34mi
Honchō	48.2°F	40mi
Yokosuka	58.7°F	42mi
Kawasaki	51.8°F	44mi
Yokohama	53.4°F	45mi

* current water temperature in this city

** straight line distance from Isumi