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 20.7°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.

69.3

°F

June 2, 01:28

Trend:

stable

Yesterday:

69.2°F

Tomorrow:

69.1°F

Sunrise:

04:25

Sunset:

18:48

Day Length:

14 h. 23 min.

Isumi in June

Minimum:

58.6°F

Average:

62.3°F

Maximum:

65.8°F

Sea water temperature in Isumi today

As of now, in Isumi, the water temperature is 69.3°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 1.1°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 fall a bit.

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 70.1°F on 2016, while the historical minimum was 65.2°F on 2024.

latest data

last year

Over the past two weeks, the water temperature has closely aligned with historical averages for those days. Over the next week, the forecast shows a steady trend, with temperatures staying close to the average of 69.1°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
May 19	65.6°F	66.2°F	65.3°F
May 20	63.2°F	66.3°F	65.3°F
May 21	65.9°F	67.0°F	65.7°F
May 22	65.9°F	68.6°F	66.1°F
May 23	66.1°F	68.3°F	66.5°F
May 24	66.1°F	66.9°F	66.9°F
May 25	66.2°F	65.6°F	66.8°F
May 26	66.3°F	66.5°F	66.9°F
May 27	66.5°F	66.1°F	67.3°F
May 28	67.0°F	67.7°F	67.5°F
May 29	67.6°F	68.3°F	68.1°F
May 30	67.6°F	66.1°F	67.8°F
May 31	68.0°F	66.4°F	68.1°F
Jun 1	69.2°F	67.6°F	68.1°F
Jun 2	69.3°F	65.2°F	68.2°F
Jun 3	69.1°F	66.1°F	68.0°F
Jun 4	68.8°F	66.6°F	67.8°F
Jun 5	69.1°F	67.1°F	68.1°F
Jun 6	69.2°F	69.2°F	68.2°F
Jun 7	69.2°F	69.3°F	68.2°F
Jun 8	69.2°F	69.4°F	68.2°F
Jun 9	69.2°F	69.9°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 103 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, 74.0°F in Summer, and 73.9°F in Autumn.

Popular neighboring cities and resorts

City	Water temperature*	Distance**
Katsuura	69.2°F	8mi
Ichihara	68.3°F	27mi
Kisarazu	68.6°F	29mi
Chiba	68.4°F	30mi
Kimitsu	68.6°F	31mi
Futtsu	68.6°F	34mi
Honchō	69.6°F	40mi
Yokosuka	68.5°F	42mi
Kawasaki	68.8°F	44mi
Yokohama	68.5°F	45mi

* current water temperature in this city

** straight line distance from Isumi