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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.
Sea temperature in Isumi now

59.1

°F

April 11, 19:55

Trend:

increasing

Yesterday:

57.1°F

Tomorrow:

59.3°F

Sunrise:

05:13

Sunset:

18:07

Day Length:

12 h. 54 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 59.1°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 1.3°F lower than the average recorded on this particular day in recent years. Since yesterday, there was a noticeable 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

The water temperature today is above average for the last two weeks, showing a small increase in temperature. 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 63.7°F on 2016, while the historical minimum was 57.7°F on 2023.

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 59.2°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 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 60.0°F
Apr 2 60.5°F 59.6°F 60.5°F
Apr 3 57.7°F 60.0°F 60.1°F
Apr 4 58.4°F 59.8°F 60.0°F
Apr 5 58.4°F 59.2°F 60.1°F
Apr 6 57.5°F 60.5°F 60.1°F
Apr 7 58.5°F 60.2°F 60.4°F
Apr 8 56.9°F 58.8°F 60.0°F
Apr 9 56.0°F 58.4°F 59.8°F
Apr 10 57.1°F 59.8°F 60.0°F
Apr 11 59.1°F 60.0°F 60.4°F
Apr 12 59.3°F 59.3°F 60.5°F
Apr 13 59.2°F 59.0°F 60.5°F
Apr 14 59.0°F 59.4°F 60.3°F
Apr 15 58.9°F 56.6°F 60.1°F
Apr 16 58.9°F 54.8°F 60.2°F
Apr 17 59.4°F 57.1°F 60.6°F
Apr 18 59.6°F 57.0°F 60.9°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

January

February

March

April

May

June

July

August

September

October

November

December

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 58.3°F 8mi
Ichihara 62.3°F 27mi
Kisarazu 61.1°F 29mi
Chiba 61.6°F 30mi
Kimitsu 60.7°F 31mi
Futtsu 60.4°F 34mi
Honchō 60.8°F 40mi
Yokosuka 60.1°F 42mi
Kawasaki 61.4°F 44mi
Yokohama 61.4°F 45mi

* current water temperature in this city

** straight line distance from Isumi