This data the coastal Otsu water temperature today, tomorrow and the upcoming days. Besides, you can also get information about the weather and surf forecast, as well as the data on sunrise / sunset and moonrise / moonset at a given point on any given day.
Water temperature in Otsu today is 29.5°C. Based on our historical data over a period of ten years, the warmest water in this day in Otsu was recorded in 2023 and was 29.2°C, and the coldest was recorded in 2015 at 24.9°C. Water temperature in Otsu is expected to drop to 26°C in the next 10 days. September average water temperature in Otsu is 25.8°C, the minimum temperature is 22.8°C, and the maximum is 30.4°C.
The swimming season in Otsu lasts from June to October. During those months, Otsu water temperature does not drop below 20°C and therefore suitable for comfortable swimming. The average water temperature in Otsu in winter reaches 11.1°C, in spring 13.1°C, in summer the average temperature rises to 24.9°C, and in autumn it is 21.5°C.
5 September 2025 |
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today temp |
29.5°C |
4 September 2025 |
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yesterday temp |
29.9°C |
Another important indicators for a comfortable holiday on the beach are the presence and height of the waves, as well as the speed and direction of the wind. Please find below data on the swell size for Otsu. We calculate the swell size based on the mean wave height (trough to crest) of each third highest wave. For more information on surf forecasts for the next ten days, please visit sea state forecast Otsu. Data in table shown for 5 September 2025, time in GMT 0 format (you can change the time zone on the sea state forecast page)
0-3 h | 3-6 h | 6-9 h | 9-12 h |
---|---|---|---|
2' 1" | 1' 4" | 1' 1" | 0' 11" |
0.64 m | 0.41 m | 0.32 m | 0.28 m |
12-15 h | 15-18 h | 18-21 h | 21-24 h |
---|---|---|---|
0' 9" | 0' 8" | 0' 7" | 0' 6" |
0.24 m | 0.2 m | 0.17 m | 0.15 m |
Data in a table show Otsu temperature today (5 September 2025). For more information and forecast for a few days, go to the weather forecast Otsu.
0-3 h | 3-6 h | 6-9 h | 9-12 h |
---|---|---|---|
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24°C | 23.5°C | 23.8°C | 23.4°C |
12-15 h | 15-18 h | 18-21 h | 21-24 h |
---|---|---|---|
![]() | ![]() | ![]() | ![]() |
20.7°C | 22.3°C | 21.9°C | 24.8°C |
You may also be interested in other sections of our site for Otsu: Sunrise and Sunset, Tides
These figures shows the average, minimum and maximum monthly water temperature in Otsu. In addition to the table values, the graph below displays of changes average surface temperature during the year. Values are calculated based on the data over the past 10 years. Using them, you can check the water temperature in Otsu on any day of this period that interests you. Click on the month link and you will see a table for each day, or alternatively you can view the temperature curve of the month and select 2 different years you want to compare, either in a table or as a curve
Month | Avr | Min | Max | |
---|---|---|---|---|
January | 10.6°C | 7.1°C | 12.9°C | cold |
Water temperature in Otsu in January | ||||
February | 9.5°C | 7.6°C | 10.8°C | cold |
Water temperature in Otsu in February | ||||
March | 9.7°C | 7°C | 13.2°C | cold |
Water temperature in Otsu in March | ||||
April | 12.7°C | 8.7°C | 17.3°C | cold |
Water temperature in Otsu in April | ||||
May | 16.9°C | 12.5°C | 22.5°C | cold |
Water temperature in Otsu in May | ||||
June | 21°C | 17.1°C | 27.6°C | warm |
Water temperature in Otsu in June | ||||
July | 25.7°C | 20.8°C | 30.9°C | hot |
Water temperature in Otsu in July | ||||
August | 27.9°C | 24.6°C | 31.4°C | hot |
Water temperature in Otsu in August | ||||
September | 25.8°C | 22.8°C | 30.4°C | hot |
Water temperature in Otsu in September | ||||
October | 21.5°C | 17.6°C | 26.7°C | warm |
Water temperature in Otsu in October | ||||
November | 17.1°C | 14.2°C | 20.1°C | cold |
Water temperature in Otsu in November | ||||
December | 13.3°C | 10.3°C | 15.9°C | cold |
Water temperature in Otsu in December |