| Copiague Beach | New York | James Bay | 21.5°C(70.7°F) | June, July, August, September | Live SST → |
| Cordreys Beach | Virginia | Coastal Waters | 24.9°C(76.8°F) | July, August, September | Live SST → |
| Corey Beach | New York | James Bay | 21.4°C(70.5°F) | June, July, August, September | Live SST → |
| Corinha Beach | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Corona del Mar State Beach | California | Gulf of California | 20.8°C(69.4°F) | July, August, September, October | Live SST → |
| Coronado Beach | California | Gulf of California | 20.8°C(69.4°F) | July, August, September, October | Live SST → |
| Coronado Shores Beach | California | Gulf of California | 20.8°C(69.4°F) | July, August, September, October | Live SST → |
| County Line Beach | California | Gulf of California | 19.4°C(66.9°F) | July, August, September, October | Live SST → |
| Cove Beach | California | Gulf of California | 14.9°C(58.8°F) | July, August, September, October | Live SST → |
| Cowell Beach | California | Gulf of California | 14.9°C(58.8°F) | August, September, October, November | Live SST → |
| Cowell Ranch Beach | California | Gulf of California | 14.9°C(58.8°F) | July, August, September, October | Live SST → |
| Craigville Beach | Massachusetts | James Bay | 19.6°C(67.3°F) | June, July, August, September | Live SST → |
| Crandall Spit | Washington | Coastal Waters | 11.4°C(52.5°F) | June, July, August, September | Live SST → |
| Crane Beach | Massachusetts | James Bay | 17.5°C(63.5°F) | June, July, August, September | Live SST → |
| Creek Club Beach | New York | James Bay | 21.7°C(71.1°F) | June, July, August, September | Live SST → |
| Crescent Beach | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Crescent Beach | Massachusetts | James Bay | 19.9°C(67.8°F) | July, August, September, October | Live SST → |
| Crescent Beach | Rhode Island | James Bay | 19.9°C(67.8°F) | July, August, September, October | Live SST → |
| Crescent Beach | New York | James Bay | 21.5°C(70.7°F) | June, July, August, September | Live SST → |
| Crescent Beach | New York | James Bay | 20.9°C(69.6°F) | July, August, September, October | Live SST → |
| Crescent Beach | Wisconsin | James Bay | 18°C(64.4°F) | July, August, September, October | Live SST → |
| Crescent Surf | Maine | James Bay | 16.5°C(61.7°F) | June, July, August, September | Live SST → |
| Crown Point Shores | California | Gulf of California | 21.2°C(70.2°F) | July, August, September, October | Live SST → |
| Crystal Beach | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Cupsoque Beach | New York | James Bay | 20.7°C(69.3°F) | July, August, September, October | Live SST → |
| Curlew Brech | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Currituck Beach | United States | Coastal Waters | 24.3°C(75.7°F) | July, August, September | Live SST → |
| D.T. Fleming Beach | Hawaii | Coastal Waters | 26.7°C(80.1°F) | January, February, March, April, May, June, July, August, September, October, November, December | Live SST → |
| Dabob Broad Spit | Washington | Coastal Waters | 11.4°C(52.5°F) | June, July, August, September | Live SST → |
| Davis Beach | Maine | James Bay | 12.3°C(54.1°F) | July, August, September, October | Live SST → |
| Dead Horse Beach | Massachusetts | James Bay | 17.5°C(63.5°F) | June, July, August, September | Live SST → |
| Del Monte Beach | California | Gulf of California | 14.9°C(58.8°F) | August, September, October, November | Live SST → |
| Destin (Emerald Coast) | Florida | Gulf of Mexico | 29°C(84.2°F) | May, Jun, Jul, Aug, Sep, Oct | Live SST → |
| Devereaux Beach | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Devils Slide Beach | California | Coastal Waters | 14.7°C(58.5°F) | July, August, September, October | Live SST → |
| Devoe Beach | Michigan | James Bay | 16.7°C(62.1°F) | July, August, September, October | Live SST → |
| Disappearing Island | Florida | Gulf of Mexico | 28.2°C(82.8°F) | May, June, July, August, September, October | Live SST → |
| Ditleff Beach | United States | Caribbean Sea | 29.2°C(84.6°F) | January, February, March, April, May, June, July, August, September, October, November, December | Live SST → |
| Dixie Beach | Florida | Gulf of Mexico | 29.8°C(85.6°F) | April, May, June, July, August, September, October, November | Live SST → |
| Dixie Maru | Hawaii | Coastal Waters | 26.9°C(80.4°F) | January, February, March, April, May, June, July, August, September, October, November, December | Live SST → |
| Dog Beach | California | Gulf of California | 21.2°C(70.2°F) | July, August, September, October | Live SST → |
| Doggie Beach | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Donkey Beach | Hawaii | North Pacific Ocean | 27°C(80.6°F) | January, February, March, April, May, June, July, August, September, October, November, December | Live SST → |
| Double Beach | United States | James Bay | 14.1°C(57.4°F) | July, August, September, October | Live SST → |
| Drakes Beach | California | Coastal Waters | 13.2°C(55.8°F) | August, September, October, November | Live SST → |
| Drakes Island Beach | Maine | James Bay | 16.5°C(61.7°F) | June, July, August, September | Live SST → |
| Driftwood Beach | California | Coastal Waters | 13.2°C(55.8°F) | August, September, October, November | Live SST → |
| Driftwood Beach | United States | James Bay | 14.1°C(57.4°F) | July, August, September, October | Live SST → |
| DuBois Beach | Connecticut | James Bay | 19.7°C(67.5°F) | July, August, September, October | Live SST → |
| Duck Harbor Beach | Massachusetts | James Bay | 18.6°C(65.5°F) | June, July, August, September | Live SST → |