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 18.94°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.

66.1

°F

November 20, 02:58

Trend:

decreasing

Yesterday:

66.1°F

Tomorrow:

65.7°F

Sunrise:

06:17

Sunset:

16:30

Day Length:

10 h. 13 min.

Isumi in November

Minimum:

58.4°F

Average:

62.3°F

Maximum:

64.7°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 66.1°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 2.8°F lower 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 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 70.9°F on 2022, while the historical minimum was 65.3°F on 2023.

latest data

last year

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 minimum recorded over the past years. Over the next week, the forecast shows a steady trend, with temperatures staying close to the average of 65.8°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
Nov 6	70.9°F	74.5°F	71.7°F
Nov 7	70.4°F	71.6°F	71.2°F
Nov 8	71.0°F	71.8°F	71.0°F
Nov 9	70.7°F	71.2°F	70.4°F
Nov 10	70.2°F	70.9°F	70.1°F
Nov 11	69.4°F	71.0°F	70.2°F
Nov 12	68.4°F	70.5°F	69.7°F
Nov 13	68.2°F	69.8°F	69.0°F
Nov 14	67.8°F	70.1°F	69.2°F
Nov 15	66.6°F	70.4°F	69.3°F
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	68.9°F
Nov 20	66.1°F	69.4°F	68.9°F
Nov 21	65.7°F	68.5°F	68.4°F
Nov 22	65.6°F	70.0°F	68.4°F
Nov 23	66.1°F	70.4°F	68.8°F
Nov 24	65.9°F	71.5°F	68.7°F
Nov 25	65.8°F	71.5°F	68.6°F
Nov 26	66.0°F	70.8°F	68.7°F
Nov 27	65.4°F	70.6°F	68.1°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	66.9°F	8mi
Ichihara	61.9°F	27mi
Kisarazu	63.1°F	29mi
Chiba	61.7°F	30mi
Kimitsu	63.2°F	31mi
Futtsu	64.0°F	34mi
Honchō	60.0°F	40mi
Yokosuka	64.8°F	42mi
Kawasaki	62.1°F	44mi
Yokohama	63.4°F	45mi

* current water temperature in this city

** straight line distance from Isumi