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 18.36°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.

65.0

°F

November 23, 04:03

Trend:

stable

Yesterday:

64.6°F

Tomorrow:

64.9°F

Sunrise:

06:20

Sunset:

16:29

Day Length:

10 h. 9 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 65.0°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 3.8°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 70.6°F on 2016, while the historical minimum was 67.3°F on 2020.

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. The forecast for the upcoming week shows a gradual cooling trend. The average temperature is expected to be 64.4°F, the minimum temperature may reach 63.7°F, and the maximum might stay at 64.9°F.

Daily water temperature in Isumi

Date	Current Year actual* / forecast**	last year	10 years average
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	68.7°F
Nov 20	66.7°F	69.4°F	68.7°F
Nov 21	64.6°F	68.5°F	68.4°F
Nov 22	64.6°F	70.0°F	68.4°F
Nov 23	65.0°F	70.4°F	68.8°F
Nov 24	64.9°F	71.5°F	68.7°F
Nov 25	64.8°F	71.5°F	68.6°F
Nov 26	64.9°F	70.8°F	68.7°F
Nov 27	64.3°F	70.6°F	68.1°F
Nov 28	64.0°F	68.3°F	67.7°F
Nov 29	64.1°F	68.4°F	67.9°F
Nov 30	63.7°F	67.2°F	67.5°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	69.7°F	8mi
Ichihara	61.3°F	27mi
Kisarazu	61.5°F	29mi
Chiba	60.8°F	30mi
Kimitsu	61.2°F	31mi
Futtsu	61.3°F	34mi
Honchō	59.5°F	40mi
Yokosuka	62.1°F	42mi
Kawasaki	60.9°F	44mi
Yokohama	61.7°F	45mi

* current water temperature in this city

** straight line distance from Isumi