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 14.55°C. 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.

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.

58.2

°F

February 26, 18:59

Trend:

decreasing

Yesterday:

58.2°F

Tomorrow:

57.4°F

Sunrise:

06:13

Sunset:

17:30

Day Length:

11 h. 17 min.

Isumi in March

Minimum:

58.8°F

Average:

62.5°F

Maximum:

66.8°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 58.2°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 1.5°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 fall 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 is also close to the historical minimum temperature for this date. The maximum temperature recorded for this date was 61.3°F on 2024, while the historical minimum was 58.3°F on 2022.

latest data

last year

Over the last two weeks, the water temperature has stayed slightly lower than historical averages for those days. The forecast for the upcoming week shows a gradual cooling trend. The average temperature is expected to be 57.0°F, the minimum temperature may reach 56.6°F, and the maximum might stay at 57.4°F.

Daily water temperature in Isumi

Date	Current Year actual* / forecast**	last year	10 years average
Feb 12	60.9°F	58.1°F	60.3°F
Feb 13	60.1°F	57.8°F	60.2°F
Feb 14	59.2°F	58.3°F	60.0°F
Feb 15	59.0°F	59.8°F	60.2°F
Feb 16	57.9°F	59.5°F	59.7°F
Feb 17	58.5°F	62.3°F	59.5°F
Feb 18	58.5°F	62.0°F	59.3°F
Feb 19	58.7°F	63.0°F	59.8°F
Feb 20	58.7°F	60.5°F	59.8°F
Feb 21	58.7°F	60.3°F	59.2°F
Feb 22	59.1°F	60.3°F	59.9°F
Feb 23	59.2°F	59.8°F	59.2°F
Feb 24	58.2°F	59.2°F	59.6°F
Feb 25	58.2°F	59.9°F	59.5°F
Feb 26	58.2°F	59.2°F	59.7°F
Feb 27	57.4°F	59.5°F	59.0°F
Feb 28	57.3°F	58.6°F	58.8°F
Mar 1	56.6°F	59.0°F	59.3°F
Mar 2	56.8°F	59.6°F	59.6°F
Mar 3	57.0°F	59.2°F	59.8°F
Mar 4	57.1°F	59.1°F	59.8°F
Mar 5	57.0°F	59.3°F	59.7°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, 74.2°F in Summer, and 74.0°F in Autumn.

Popular neighboring cities and resorts

City	Water temperature*	Distance**
Katsuura	58.8°F	8mi
Ichihara	56.3°F	27mi
Kisarazu	55.6°F	29mi
Chiba	56.2°F	30mi
Kimitsu	54.8°F	31mi
Futtsu	55.3°F	34mi
Honchō	54.9°F	40mi
Yokosuka	55.4°F	42mi
Kawasaki	53.0°F	44mi
Yokohama	53.2°F	45mi

* current water temperature in this city

** straight line distance from Isumi