Coldest sea in United States

4,477 coastal locations in United States ranked by year-round average sea temperature, coldest first. The regional average is 16.2°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

Prudhoe Bay #2

Year-round average -0.3°C in United States

Regional average

16.2°C

across all 4,477 United States coastal locations

Coldest month

February

10.0°C region-wide average

United States monthly average 10.0°C to 22.6°C

Warmest month August 22.6°C
Coldest month February 10.0°C
Annual mean 16.2°C
Months above 20°C 3 of 12

Month by month across United States

Sea temperatures in United States swing from 10.0°C in February to 22.6°C in August on average across every coast we track. That spread of 13°C hides much bigger swings at individual locations.

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

United States sea temperature map

Today's pin colours show the latest daily reading at every United States 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 United States

Coastal locations across United States 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	Prudhoe Bay #2 Alaska	United States	-0.3°C	-1.5°C
2	Prudhoe Bay Alaska	United States	-0.3°C	-1.5°C
3	Flaxman Island Alaska	United States	-0.3°C	-1.5°C
4	Cross Island (Dinkum Sands) Alaska	United States	-0.3°C	-1.5°C
5	Barrow Alaska	United States	-0.2°C	-1.6°C
6	Barter Island Alaska	United States	-0.1°C	-1.6°C
7	Barrow (offshore) Alaska	United States	0.1°C	-1.6°C
8	Point Barrow, Alaska Alaska	United States	0.1°C	-1.6°C
9	Point Barrow Alaska	United States	0.1°C	-1.6°C
10	Maknik Lagoon entrance, St. Lawrence Island, Alaska Alaska	United States	1.5°C	-1.4°C
11	Northeast Cape, St. Lawrence Island Alaska	United States	1.6°C	-1.5°C
12	Lake Sakakawea North Dakota	United States	1.6°C	-1.4°C
13	Point Hope Alaska	United States	1.6°C	-1.5°C
14	Fossil River entrance, St. Lawrence Island, Alaska Alaska	United States	1.6°C	-1.2°C
15	Fort Peck Lake Montana	United States	1.7°C	-1.5°C
16	Kivalina Alaska	United States	1.7°C	-1.6°C
17	Cape Espenberg, Kotzebue Sound Alaska	United States	1.7°C	-1.7°C
18	Savoonga, St. Lawrence Island Alaska	United States	1.7°C	-1.0°C
19	Red Dog Dock Alaska	United States	1.8°C	-1.5°C
20	Outside Lopp Lagoon Alaska	United States	1.9°C	-1.6°C
21	Shishmaref Inlet 2 Alaska	United States	1.9°C	-1.4°C
22	Powooiliak Point, St. Lawrence Island, Alaska Alaska	United States	1.9°C	-1.0°C
23	Akeftapak, St. Lawrence Island Alaska	United States	1.9°C	-1.1°C
24	Tin City, Bering Sea Alaska	United States	1.9°C	-1.7°C
25	Cape Krusenstern, Kotzebue Sound Alaska	United States	2.0°C	-1.6°C

Show 25 more ▸

26	Goodhope Bay, Kotzebue Sound Alaska	United States	2.0°C	-1.5°C
27	Moghoweyik River entrance, St. Lawrence Island, Alaska Alaska	United States	2.0°C	-1.2°C
28	Kotzebue, Kotzebue Sound Alaska	United States	2.2°C	-1.5°C
29	Deering, Kotzebue Sound Alaska	United States	2.2°C	-1.5°C
30	Lost River, Seward Peninsula Alaska	United States	2.3°C	-1.5°C
31	Kiwalik, Kotzebue Sound, Alaska Alaska	United States	2.3°C	-1.4°C
32	Teller, Port Clarance, Norton Sound, Alaska Alaska	United States	2.4°C	-1.4°C
33	Teller, Port Clarence Alaska	United States	2.4°C	-1.4°C
34	Point Spencer, Port Clarence, Norton Sound Alaska	United States	2.5°C	-1.4°C
35	St. Matthew Island, Bering Sea, Alaska Alaska	United States	2.5°C	-1.0°C
36	Kotzebue Alaska	United States	2.6°C	-1.5°C
37	Nome, Norton Sound Alaska	United States	2.9°C	-1.2°C
38	Mekoryuk, Mekoryuk River Entrance Alaska	United States	3.0°C	-1.2°C
39	Eastern Nunivak Island Alaska	United States	3.3°C	-0.9°C
40	Nome Alaska	United States	3.3°C	-1.2°C
41	Cape Romanzof, Bering Sea, Alaska Alaska	United States	3.4°C	1.3°C
42	Dall Point, Hooper Bay Alaska	United States	3.4°C	1.0°C
43	Kokechik Bay, Bering Sea, Alaska Alaska	United States	3.5°C	1.5°C
44	Tooksook Bay, Nelson Island Alaska	United States	3.5°C	-0.1°C
45	Apoon Mouth, Yukon River, Norton Sound, Alaska Alaska	United States	3.6°C	-1.2°C
46	Pikmiktalik River entrance, Norton Sound, Alaska Alaska	United States	3.6°C	-0.8°C
47	Black, Black River, Bering Sea, Alaska Alaska	United States	3.7°C	2.9°C
48	North Bay, Stuart Island, Norton Sound, Alaska Alaska	United States	3.7°C	0.1°C
49	Shaktoolik Alaska	United States	3.7°C	0.8°C
50	St. Michael, Norton Sound Alaska	United States	3.8°C	2.4°C

Warmest 10 in United States for contrast

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

#	Location	Country	Annual mean
1	Palmyra Island Northern Line Islands	United States	28.5°C
2	Howland Island Minor Outlying Islands	United States	28.4°C
3	Wake Island, Pacific Ocean Minor Outlying Islands	United States	27.9°C
4	Long Island New York	United States	27.7°C
5	Boynton Beach, Lake Worth Florida	United States	27.7°C
6	Lake Worth ICW Florida	United States	27.7°C
7	Lake Worth (ICWW) Florida	United States	27.7°C
8	Lake Worth Pier, Florida	United States	27.7°C
9	Palm Beach, Highway 704 bridge, Lake Worth, Florida Florida	United States	27.7°C
10	Palm Beach, Lake Worth, Florida Florida	United States	27.7°C