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 21.67°C. Swimming in water of this temperature is seen as relatively warm and enjoyable for some individuals, although many might find it slightly too cool.

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.

71.0

°F

November 30, 04:06

Trend:

decreasing

Yesterday:

71.4°F

Tomorrow:

71.0°F

Sunrise:

06:27

Sunset:

16:26

Day Length:

9 h. 59 min.

Isumi in December

Minimum:

56.7°F

Average:

61.8°F

Maximum:

65.7°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 71.0°F. Swimming in water of this temperature is seen as relatively warm and enjoyable for some individuals, although many might find it slightly too cool. Today's reading is 3.5°F higher 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 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 is also close to the historical maximum temperature for this date. The maximum temperature recorded for this date was 69.0°F on 2019, while the historical minimum was 63.7°F on 2021.

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. The forecast for the upcoming week shows a gradual cooling trend. The average temperature is expected to be 70.2°F, the minimum temperature may reach 69.6°F, and the maximum might stay at 71.0°F.

Daily water temperature in Isumi

Date	Current Year actual* / forecast**	last year	10 years average
Nov 16	67.6°F	71.0°F	69.2°F
Nov 17	65.6°F	71.1°F	68.9°F
Nov 18	66.4°F	71.5°F	68.8°F
Nov 19	66.1°F	70.5°F	68.7°F
Nov 20	66.7°F	69.4°F	68.7°F
Nov 21	64.6°F	68.5°F	68.1°F
Nov 22	64.4°F	70.0°F	68.0°F
Nov 23	65.0°F	70.4°F	68.5°F
Nov 24	66.0°F	71.5°F	68.4°F
Nov 25	64.9°F	71.5°F	68.3°F
Nov 26	66.7°F	70.8°F	68.6°F
Nov 27	71.3°F	70.6°F	68.4°F
Nov 28	72.1°F	68.3°F	68.1°F
Nov 29	71.4°F	68.4°F	67.9°F
Nov 30	71.0°F	67.2°F	67.5°F
Dec 1	71.0°F	67.0°F	67.5°F
Dec 2	70.5°F	67.0°F	67.0°F
Dec 3	70.4°F	66.3°F	66.9°F
Dec 4	70.5°F	66.7°F	67.0°F
Dec 5	69.8°F	65.8°F	66.3°F
Dec 6	69.8°F	66.8°F	66.3°F
Dec 7	69.6°F	66.9°F	66.1°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 108 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, 61.9°F in Spring, 74.2°F in Summer, and 73.9°F in Autumn.

Popular neighboring cities and resorts

City	Water temperature*	Distance**
Katsuura	73.2°F	8mi
Ichihara	61.4°F	27mi
Kisarazu	62.1°F	29mi
Chiba	61.3°F	30mi
Kimitsu	62.0°F	31mi
Futtsu	64.4°F	34mi
Honchō	59.0°F	40mi
Yokosuka	67.0°F	42mi
Kawasaki	60.6°F	44mi
Yokohama	61.2°F	45mi

* current water temperature in this city

** straight line distance from Isumi