Where is the sea warmest in North America in September?
In September the warmest sea in North America is at San Felipe, Mexico, at 31.1°C. 67 of 103 cities measured are comfortable this month.
| # | City | Country | Sea | Swimming |
|---|---|---|---|---|
| 1 | San Felipe | Mexico | 31.1°C | Bath-like |
| 2 | Campeche | Mexico | 30.6°C | Bath-like |
| 3 | Mazatlán | Mexico | 30.4°C | Bath-like |
| 4 | Puerto Vallarta | Mexico | 30.4°C | Bath-like |
| 5 | Ciudad del Carmen | Mexico | 30.4°C | Bath-like |
| 6 | La Cruz | Mexico | 30.4°C | Bath-like |
| 7 | Chetumal | Mexico | 30.4°C | Bath-like |
| 8 | Key West | United States | 30.4°C | Bath-like |
| 9 | Naples | United States | 30.3°C | Bath-like |
| 10 | Cape Coral | United States | 30.3°C | Bath-like |
| 11 | Acapulco de Juárez | Mexico | 30.2°C | Bath-like |
| 12 | Salina Cruz | Mexico | 30.2°C | Bath-like |
| 13 | Coatzacoalcos | Mexico | 30.0°C | Bath-like |
| 14 | Pompano Beach | United States | 30.0°C | Bath-like |
| 15 | Miami | United States | 30.0°C | Bath-like |
| 16 | Manzanillo | Mexico | 30.0°C | Bath-like |
| 17 | Hollywood | United States | 30.0°C | Bath-like |
| 18 | West Palm Beach | United States | 30.0°C | Bath-like |
| 19 | Bradenton | United States | 30.0°C | Bath-like |
| 20 | Veracruz | Mexico | 30.0°C | Bath-like |
| 21 | Playa del Carmen | Mexico | 29.8°C | Bath-like |
| 22 | Largo | United States | 29.7°C | Bath-like |
| 23 | Cancún | Mexico | 29.6°C | Bath-like |
| 24 | Tarpon Springs | United States | 29.6°C | Bath-like |
| 25 | New Orleans | United States | 29.4°C | Bath-like |
Ranked on the NOAA OISST monthly climatology — a long-run average for September, not a forecast. A given September will run warmer or cooler than this, and the sea is warmest late in the afternoon and late in the season.