Coldest sea in Japan

373 coastal locations in Japan ranked by year-round average sea temperature, coldest first. The regional average is 19.1°C. The top of the list is where the water stays cold all year. The contrast list at the bottom shows the warmest coasts for context.

Coldest location

Moyoro Wan

Year-round average 6.1°C in Japan

Regional average

19.1°C

across all 373 Japan coastal locations

Coldest month

February

12.8°C region-wide average

Japan monthly average 12.8°C to 26.6°C

Warmest month August 26.6°C
Coldest month February 12.8°C
Annual mean 19.1°C
Months above 20°C 5 of 12

Month by month across Japan

Sea temperatures in Japan swing from 12.8°C in February to 26.6°C in August on average across every coast we track. That spread of 14°C hides much bigger swings at individual locations.

Want a specific month? Pick one for a dedicated ranking:

Japan sea temperature map

Today's pin colours show the latest daily reading at every Japan location we track. Cool blues cluster around the high-latitude coasts.

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 coldest locations in Japan

Coastal locations across Japan sorted by year-round average, coldest first. Honest cold-water swimming country. Click any place for its 30-day chart, monthly profile, and 10-year history.

#	Location	Country	Annual mean	Latest
1	Moyoro Wan Hokkaido	Japan	6.1°C	2.5°C
2	Shibetoro Hokkaido	Japan	6.6°C	2.1°C
3	Hitokappi Wan Hokkaido	Japan	6.8°C	2.3°C
4	Shana Wan Hokkaido	Japan	6.9°C	2.0°C
5	Naibo Wan Hokkaido	Japan	7.0°C	2.0°C
6	Mombetsu	Japan	7.9°C	6.2°C
7	Koiseboi Hokkaido	Japan	8.2°C	3.5°C
8	Abashiri Ko Hokkaido	Japan	8.2°C	5.1°C
9	Furukamappu Wan Hokkaido	Japan	8.3°C	4.0°C
10	Hanasaki Hokkaido	Japan	8.3°C	6.3°C
11	Nemuro Ko Hokkaido	Japan	8.3°C	6.3°C
12	Hojo	Japan	8.5°C	7.0°C
13	Shibetsu	Japan	8.6°C	8.9°C
14	Monbetsu Hokkaido	Japan	8.6°C	7.6°C
15	Tomari Wan Hokkaido	Japan	8.8°C	6.7°C
16	Kiritappu Hokkaido	Japan	8.9°C	5.4°C
17	Omu Ko Hokkaido	Japan	9.0°C	8.9°C
18	Akkeshi Hokkaido	Japan	9.0°C	6.0°C
19	Esashi (Hokkaido Ne Coast) Hokkaido	Japan	9.1°C	8.3°C
20	Hokkaido	Japan	9.2°C	6.8°C
21	Shizunai	Japan	9.3°C	7.4°C
22	Kushiro	Japan	9.4°C	6.0°C
23	Rubeshibetsu Hokkaido	Japan	9.5°C	6.0°C
24	Soya Misaki Hokkaido	Japan	9.9°C	7.3°C
25	Wakkanai	Japan	10.6°C	7.9°C

Show 25 more ▸

26	Erimo Misaki Hokkaido	Japan	10.8°C	6.2°C
27	Urakawa Hokkaido	Japan	11.2°C	7.0°C
28	Sakai	Japan	11.3°C	10.5°C
29	Tomakomai	Japan	11.8°C	9.4°C
30	Oshidomari Wan Hokkaido	Japan	12.2°C	8.7°C
31	Hakodate	Japan	12.2°C	10.2°C
32	Noboribetsu	Japan	12.2°C	9.4°C
33	Usujiri Hokkaido	Japan	12.3°C	9.8°C
34	Muroran Hokkaidō	Japan	12.3°C	9.9°C
35	Usu Wan Hokkaido	Japan	12.3°C	9.9°C
36	Mori Ko Hokkaido	Japan	12.4°C	10.2°C
37	Tomamae Hokkaido	Japan	12.9°C	10.0°C
38	Ishikari	Japan	13.1°C	11.6°C
39	Sapporo	Japan	13.1°C	11.6°C
40	Mikuni	Japan	13.1°C	11.3°C
41	Muta	Japan	13.1°C	11.3°C
42	Rumoi Hokkaido	Japan	13.1°C	11.2°C
43	Otaru	Japan	13.2°C	10.9°C
44	Yoichi	Japan	13.2°C	10.9°C
45	Kamui Misaki Hokkaido	Japan	13.7°C	11.0°C
46	Hachinohe	Japan	14.2°C	11.9°C
47	Kuji Iwate	Japan	14.4°C	11.3°C
48	Miyako	Japan	14.4°C	10.7°C
49	Setana Hokkaido	Japan	14.6°C	12.3°C
50	Shiriya Aomori	Japan	14.6°C	11.7°C

Warmest 10 in Japan for contrast

Same data flipped. Useful if you want to know which Japan coasts stay warmest year-round before you commit to a cold-water swim trip.

#	Location	Country	Annual mean
1	Minami-Tori Shima Tokyo	Japan	27.2°C
2	Yonakuni Shima Okinawa	Japan	27.0°C
3	Yonakuni	Japan	26.9°C
4	Funauke Okinawa	Japan	26.7°C
5	lo Shima Tokyo	Japan	26.6°C
6	Ishigaki	Japan	26.5°C
7	Kobi Sho Okinawa	Japan	26.5°C
8	Hirara Okinawa	Japan	26.3°C
9	Miyakojima	Japan	26.3°C
10	Kanegusuku Okinawa	Japan	25.8°C