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 16.17°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.

61.1

°F

April 2, 05:28

Trend:

stable

Yesterday:

60.6°F

Tomorrow:

61.0°F

Sunrise:

05:25

Sunset:

18:00

Day Length:

12 h. 35 min.

Isumi in April

Minimum:

58.8°F

Average:

62.2°F

Maximum:

66.6°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 61.1°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 0.6°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 stay about the same.

Recent sea temperature and forecast

Today's water temperature is notably higher than the average recorded over the past two weeks, indicating a significant warming 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 62.3°F on 2021, while the historical minimum was 59.3°F on 2024.

latest data

last year

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 61.0°F. Both minimum and maximum temperatures expected to be close to the average, offering a week of stable water conditions.

Daily water temperature in Isumi

Date	Current Year actual* / forecast**	last year	10 years average
Mar 19	58.2°F	58.1°F	59.1°F
Mar 20	58.0°F	58.5°F	59.8°F
Mar 21	57.8°F	58.6°F	59.4°F
Mar 22	58.0°F	59.5°F	59.8°F
Mar 23	58.2°F	59.0°F	59.8°F
Mar 24	57.1°F	58.2°F	60.0°F
Mar 25	58.1°F	58.6°F	60.0°F
Mar 26	58.6°F	60.4°F	60.4°F
Mar 27	57.2°F	59.7°F	60.0°F
Mar 28	59.4°F	61.9°F	60.3°F
Mar 29	57.8°F	60.4°F	60.1°F
Mar 30	59.4°F	60.4°F	60.4°F
Mar 31	59.8°F	60.5°F	60.5°F
Apr 1	60.6°F	59.7°F	59.9°F
Apr 2	61.1°F	59.6°F	60.5°F
Apr 3	61.0°F	60.0°F	60.4°F
Apr 4	60.8°F	59.8°F	60.2°F
Apr 5	60.9°F	59.2°F	60.3°F
Apr 6	61.0°F	60.5°F	60.4°F
Apr 7	61.3°F	60.2°F	60.6°F
Apr 8	60.9°F	58.8°F	60.3°F
Apr 9	60.8°F	58.4°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	61.6°F	8mi
Ichihara	58.3°F	27mi
Kisarazu	59.7°F	29mi
Chiba	58.6°F	30mi
Kimitsu	59.8°F	31mi
Futtsu	59.8°F	34mi
Honchō	59.3°F	40mi
Yokosuka	58.7°F	42mi
Kawasaki	60.5°F	44mi
Yokohama	59.5°F	45mi

* current water temperature in this city

** straight line distance from Isumi