| Shore Beach | New Jersey | Coastal Waters | 22.3°C(72.1°F) | July, August, September | Live SST → |
| Shoreham Beach | New York | James Bay | 21.2°C(70.2°F) | June, July, August, September | Live SST → |
| Short Beach | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Short Beach | New York | James Bay | 20.9°C(69.6°F) | July, August, September, October | Live SST → |
| Short Beach | New York | James Bay | 21.4°C(70.5°F) | June, July, August, September | Live SST → |
| Short Beach | Connecticut | James Bay | 22.3°C(72.1°F) | July, August, September | Live SST → |
| Short Beach | Oregon | Coastal Waters | 14.2°C(57.6°F) | June, July, August, September | Live SST → |
| Short Sand Beach | Oregon | Coastal Waters | 14.2°C(57.6°F) | June, July, August, September | Live SST → |
| Short Sands Beach | Maine | James Bay | 16.9°C(62.4°F) | June, July, August, September | Live SST → |
| Siesta Key (Sarasota) | Florida | Gulf of Mexico | 29.8°C(85.6°F) | May, Jun, Jul, Aug, Sep, Oct | Live SST → |
| Silver Lake Town Beach | Massachusetts | James Bay | 17.6°C(63.7°F) | June, July, August, September | Live SST → |
| Silver Sands Beach | Connecticut | James Bay | 22.1°C(71.8°F) | July, August, September | Live SST → |
| Silver Strand State Beach | California | Gulf of California | 19.4°C(66.9°F) | July, August, September, October | Live SST → |
| Simmons Island Beach | Wisconsin | James Bay | 19.3°C(66.7°F) | July, August, September, October | Live SST → |
| Singing Beach | Massachusetts | James Bay | 17.5°C(63.5°F) | June, July, August, September | Live SST → |
| Slaughter Beach | Delaware | Coastal Waters | 23.1°C(73.6°F) | July, August, September | Live SST → |
| Slaughter House Beach | Hawaii | Coastal Waters | 26.7°C(80.1°F) | January, February, March, April, May, June, July, August, September, October, November, December | Live SST → |
| Slide Ranch North Beach | California | Coastal Waters | 14.5°C(58.1°F) | July, August, September, October | Live SST → |
| Smathers Beach | Florida | Gulf of Mexico | 29.8°C(85.6°F) | April, May, June, July, August, September, October, November, December | Live SST → |
| Smith Beach | Virginia | Coastal Waters | 24.5°C(76.1°F) | July, August, September | Live SST → |
| Smith Island Beach | Virginia | Coastal Waters | 24.4°C(75.9°F) | July, August, September | Live SST → |
| Snee-oosh Beach | Washington | Coastal Waters | 11.4°C(52.5°F) | June, July, August, September | Live SST → |
| Sombrero Beach | United States | Gulf of Mexico | 29.6°C(85.3°F) | March, April, May, June, July, August, September, October, November, December | Live SST → |
| Sonofa 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 → |
| Sooes Beach | Washington | Coastal Waters | 12.2°C(54°F) | June, July, August, September | Live SST → |
| Sound Beach | Virginia | Coastal Waters | 24.8°C(76.6°F) | July, August, September | Live SST → |
| Soundview Beach | Connecticut | James Bay | 20.9°C(69.6°F) | July, August, September, October | Live SST → |
| South Beach | California | Coastal Waters | 13.2°C(55.8°F) | August, September, October, November | Live SST → |
| South Beach | California | Gulf of California | 19.4°C(66.9°F) | July, August, September, October | Live SST → |
| South Beach | Massachusetts | Coastal Waters | 19.1°C(66.4°F) | July, August, September, October | Live SST → |
| South Beach | New York | James Bay | 21.8°C(71.2°F) | June, July, August, September | Live SST → |
| South Beach | Michigan | James Bay | 20°C(68°F) | July, August, September, October | Live SST → |
| South Beach | Wisconsin | James Bay | 18.7°C(65.7°F) | July, August, September, October | Live SST → |
| South Boulevard Beach | Illinois | James Bay | 20.1°C(68.2°F) | July, August, September, October | Live SST → |
| South Cape Beach | Massachusetts | James Bay | 20.2°C(68.4°F) | June, July, August, September | Live SST → |
| South Jetty Beach | California | Gulf of California | 19.2°C(66.6°F) | July, August, September, October | Live SST → |
| South Oceanside Beach | California | Gulf of California | 21.3°C(70.3°F) | July, August, September, October | Live SST → |
| South Padre Island | Texas | Gulf of Mexico | 29.4°C(84.9°F) | May, Jun, Jul, Aug, Sep, Oct | Live SST → |
| South Pine Creek Beach | Connecticut | James Bay | 22.3°C(72.1°F) | July, August, September | Live SST → |
| South Sandy Beach | United States | James Bay | 14.2°C(57.6°F) | July, August, September, October | Live SST → |
| South Shore Beach | Rhode Island | James Bay | 19.7°C(67.5°F) | July, August, September, October | Live SST → |
| South Shore Beach | Illinois | James Bay | 20.2°C(68.4°F) | July, August, September, October | Live SST → |
| Southampton Beach | New York | James Bay | 20.7°C(69.3°F) | July, August, September, October | Live SST → |
| Southport Beach | Connecticut | James Bay | 22.3°C(72.1°F) | July, August, September | Live SST → |
| Spanish Landing Beach | California | Gulf of California | 20.8°C(69.4°F) | July, August, September, October | Live SST → |
| Spitting caves | Hawaii | Coastal Waters | 26.8°C(80.2°F) | January, February, March, April, May, June, July, August, September, October, November, December | Live SST → |
| Spragues Beach | Maine | James Bay | 14.6°C(58.3°F) | July, August, September, October | Live SST → |
| Sprat Hall 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 → |
| Stannard Beach | Connecticut | James Bay | 20.9°C(69.6°F) | July, August, September, October | Live SST → |
| State Park Beach | South Carolina | Gulf of Mexico | 27.1°C(80.8°F) | June, July, August, September | Live SST → |