In December warmest sea in Japan is usually observed in the following locations: Okinawa, Nagasaki, Atami.
Table below shows the average sea water temperature for marine resorts of Japan in December for the last three years.
| Place name | December 2025 | December 2024 | December 2023 |
|---|---|---|---|
| Okinawa | 75.9°F | 75.3°F | 75.2°F |
| Nagasaki | 67.6°F | 64.1°F | 64.1°F |
| Atami | 66.7°F | 65.8°F | 63.5°F |
| Hakone | 66.3°F | 65.7°F | 63.5°F |
| Kamakura | 65.9°F | 65.1°F | 63.1°F |
| Fukuoka | 63.2°F | 62.2°F | 62.2°F |
| Hiroshima | 62.6°F | 61.6°F | 60.9°F |
| Yokohama | 61.4°F | 60.4°F | 59.7°F |
| Kobe | 61.3°F | 60.1°F | 60.1°F |
| Osaka | 60.4°F | 58.7°F | 59.2°F |
| Nagoya | 60.2°F | 60.7°F | 59.9°F |
| Nara | 59.9°F | 58.2°F | 58.4°F |
| Tokyo | 59.5°F | 58.4°F | 58.6°F |
| Kyoto | 58.1°F | 56.4°F | 56.3°F |
| Noboribetsu | 50.6°F | 50.2°F | 46.3°F |
| Sapporo | 45.7°F | 45.2°F | 47.3°F |
Charts below show average sea water temperature for Japan resorts with the warmest sea in December.
You can also check other months of the year to see sea temperature of Japan resorts at that time.
Places in Japan:
Name
°F
