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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

58.7

°F

February 19, 18:53

Trend:

increasing

Yesterday:

58.5°F

Tomorrow:

58.7°F

Sunrise:

06:21

Sunset:

17:24

Day Length:

11 h. 3 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 58.7°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 1.2°F lower 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 considerably 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 63.0°F on 2025, while the historical minimum was 57.5°F on 2021.

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. Over the next week, the forecast shows a steady trend, with temperatures staying close to the average of 58.4°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
Feb 5 62.0°F 61.2°F 60.4°F
Feb 6 61.3°F 60.8°F 60.0°F
Feb 7 61.3°F 59.8°F 59.8°F
Feb 8 62.2°F 57.3°F 59.5°F
Feb 9 62.7°F 57.4°F 59.9°F
Feb 10 62.7°F 57.2°F 59.8°F
Feb 11 62.5°F 58.4°F 60.0°F
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 59.9°F
Feb 20 58.7°F 60.5°F 60.0°F
Feb 21 58.0°F 60.3°F 59.3°F
Feb 22 58.8°F 60.3°F 60.0°F
Feb 23 58.0°F 59.8°F 59.2°F
Feb 24 58.5°F 59.2°F 59.7°F
Feb 25 58.5°F 59.9°F 59.7°F
Feb 26 58.5°F 59.2°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

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 59.8°F 8mi
Ichihara 57.7°F 27mi
Kisarazu 58.8°F 29mi
Chiba 57.4°F 30mi
Kimitsu 59.1°F 31mi
Futtsu 58.5°F 34mi
Honchō 57.6°F 40mi
Yokosuka 58.4°F 42mi
Kawasaki 59.9°F 44mi
Yokohama 58.1°F 45mi

* current water temperature in this city

** straight line distance from Isumi