The Japan resorts with the warmest sea water temperature in January are Okinawa, Nagasaki and Hakone.
Below you can see a list of all popular Japan resorts and information about sea water temperature in January for the last two years.
| Resort Name | January 2026 | January 2025 | January 2024 |
|---|---|---|---|
| Okinawa | 73.9°F | 74.0°F | 75.3°F |
| Nagasaki | 63.3°F | 61.5°F | 61.7°F |
| Hakone | 61.7°F | 62.2°F | 63.3°F |
| Atami | 61.5°F | 62.3°F | 63.4°F |
| Kamakura | 60.8°F | 62.3°F | 63.4°F |
| Fukuoka | 57.7°F | 57.6°F | 58.7°F |
| Hiroshima | 57.1°F | 56.8°F | 57.8°F |
| Yokohama | 55.1°F | 56.5°F | 55.9°F |
| Nagoya | 53.5°F | 54.2°F | 56.4°F |
| Kobe | 53.1°F | 52.8°F | 54.2°F |
| Osaka | 52.9°F | 51.2°F | 54.1°F |
| Nara | 52.7°F | 51.3°F | 53.9°F |
| Tokyo | 52.1°F | 53.2°F | 54.4°F |
| Kyoto | 52.1°F | 50.7°F | 53.3°F |
| Noboribetsu | 42.8°F | 42.6°F | 41.4°F |
| Sapporo | 38.4°F | 40.7°F | 42.6°F |
Please see following sea water temperature averages charts for the warmest Japan resorts in January.
You can also get the same information for the every other month of the year when the average sea water temperature is greater then 70°F.
