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 16.93°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.

62.5

°F

May 11, 20:25

Trend:

stable

Yesterday:

62.3°F

Tomorrow:

62.1°F

Sunrise:

04:38

Sunset:

18:32

Day Length:

13 h. 54 min.

Isumi in May

Minimum:

56.8°F

Average:

61.9°F

Maximum:

66.3°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 62.5°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 2.1°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 fall a bit.

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 66.3°F on 2023, while the historical minimum was 62.5°F on 2021.

latest data

last year

Observations from the last two weeks indicate that the water temperature was in proximity to the highest 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 62.2°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
Apr 27	67.0°F	59.8°F	63.4°F
Apr 28	66.4°F	61.7°F	62.9°F
Apr 29	65.6°F	61.8°F	62.5°F
Apr 30	65.7°F	59.1°F	62.2°F
May 1	65.5°F	59.6°F	62.3°F
May 2	64.0°F	60.2°F	61.9°F
May 3	65.2°F	60.9°F	62.4°F
May 4	66.7°F	61.2°F	62.7°F
May 5	64.0°F	60.9°F	62.5°F
May 6	63.3°F	61.5°F	62.7°F
May 7	64.0°F	62.3°F	63.2°F
May 8	65.4°F	61.4°F	63.4°F
May 9	60.5°F	62.8°F	63.2°F
May 10	62.3°F	63.4°F	63.8°F
May 11	62.5°F	64.2°F	64.6°F
May 12	62.1°F	63.9°F	64.3°F
May 13	61.8°F	63.4°F	64.0°F
May 14	61.6°F	62.9°F	63.8°F
May 15	62.1°F	64.1°F	64.3°F
May 16	62.5°F	64.6°F	64.6°F
May 17	62.4°F	64.9°F	64.5°F
May 18	62.6°F	65.4°F	64.8°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	64.8°F	8mi
Ichihara	66.0°F	27mi
Kisarazu	68.8°F	29mi
Chiba	66.8°F	30mi
Kimitsu	68.0°F	31mi
Futtsu	66.9°F	34mi
Honchō	71.0°F	40mi
Yokosuka	65.4°F	42mi
Kawasaki	67.5°F	44mi
Yokohama	66.8°F	45mi

* current water temperature in this city

** straight line distance from Isumi