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Warmest sea in Japan in January

373 coastal locations in Japan ranked by their typical January sea temperature. Region-wide average in January: 14.1°C. The top of the list is where to find the warmest swimming this month.

Warmest in January

Minami-Tori Shima

25.4°C January mean in Japan

Regional January average

14.1°C

across all 373 coastal locations in Japan

Vs annual mean

-5.0°C

below the year-round regional average

What the Japan sea feels like in January

Water at this temperature is cold and will feel very cold initially, but the body will get used to it and longer swims are possible. Experienced swimmers can manage several hours of swimming, however hypothermia is still a real risk.

Japan monthly average 12.8°C to 26.6°C
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F
M
A
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  • Warmest month August 26.6°C
  • Coldest month February 12.8°C
  • Annual mean 19.1°C
  • Months above 20°C 5 of 12

Where January fits in the year

January sits inside the regional pattern shown on the left. Pick a different month to see how the ranking shifts.

All twelve Japan month rankings:

Japan sea temperature map (live)

The map shows today's latest reading at every Japan location. The list below is based on the typical January mean, useful for trip planning weeks or months ahead.

Zoom in to see individual locations. Click a pin for water temperatures. View list →
°C -2 0 1 3 5 7 9 11 13 15 17 19 21 24 27 30 35

Top 50 warmest Japan locations in January

Sorted by the typical January mean built from a decade of daily readings at each location. Click any place for its 30-day chart, monthly profile, and full 10-year history.

# Location January mean
1 Minami-Tori Shima Tokyo 25.4°C
2 Yonakuni 24.2°C
3 Yonakuni Shima Okinawa 24.1°C
4 Kobi Sho Okinawa 23.7°C
5 lo Shima Tokyo 23.6°C
6 Funauke Okinawa 23.6°C
7 Ishigaki 23.6°C
8 Miyakojima 23.4°C
9 Hirara Okinawa 23.2°C
10 Minami-Daito Shima Okinawa 22.9°C
11 Kanegusuku Okinawa 22.7°C
12 Tsuhako Okinawa 22.7°C
13 Kerama Kaikyo (Zamami) Okinawa 22.6°C
14 Naha Ko Okinawa 22.6°C
15 Haebaru 22.5°C
16 Itoman 22.5°C
17 Okinawa 22.5°C
18 Tomigusuku 22.5°C
19 Nakano Shima Kagoshima 22.5°C
20 Chatan 22.3°C
21 Gushikawa 22.3°C
22 Suku Okinawa 22.3°C
23 Nago 22.2°C
24 Takara Shima Kagoshima 22.2°C
25 Toguchi Okinawa 22.2°C
Show 25 more ▸
26 Wadomari Kagoshima 22.1°C
27 Gakiya Okinawa 22.1°C
28 Haha Shima Tokyo 22.0°C
29 Kuchi-No-Erabu Shima Kagoshima 22.0°C
30 Amami 21.9°C
31 Sanmura Wan Kagoshima 21.9°C
32 Koniya Kagoshima 21.9°C
33 Kasari Wan Kagoshima 21.8°C
34 Uken Kagoshima 21.8°C
35 Chichi Shima Tokyo 21.7°C
36 Ogasawara 21.6°C
37 Isso Kagoshima 21.3°C
38 Kumano Kagoshima 21.1°C
39 Yakushima 20.8°C
40 Tori Shima Tokyo 20.6°C
41 Hachijo Jima Tokyo 20.5°C
42 Nishinoomote 20.1°C
43 Miyake Shima Tokyo 19.8°C
44 Makurazaki 19.8°C
45 Kozu Sima Tokyo 19.7°C
46 Shibushi 19.6°C
47 Aburatsu Miyazaki 19.6°C
48 Uchiumi Miyazaki 19.6°C
49 Miyazaki Shi 19.5°C
50 Odomari Kagoshima 19.3°C

Coldest 10 in Japan in January

Same data the other way. Helpful if you want to know which Japan coasts to avoid for swimming in January.

# Location January mean
1 Hojo -0.4°C
2 Mombetsu -0.2°C
3 Monbetsu Hokkaido -0.1°C
4 Abashiri Ko Hokkaido -0.1°C
5 Shibetsu 0.0°C
6 Omu Ko Hokkaido 0.1°C
7 Koiseboi Hokkaido 0.5°C
8 Esashi (Hokkaido Ne Coast) Hokkaido 0.5°C
9 Hanasaki Hokkaido 1.4°C
10 Nemuro Ko Hokkaido 1.4°C

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