| Rosario Olinda | Eastern Australia Time | -14:00 |
| Rosario Old Basing | United Kingdom Time | -03:00 |
| Rosario Okeechobee | Eastern Time | 02:00 |
| Rosario Okehampton | United Kingdom Time | -03:00 |
| Rosario Oeiras | Western European Time | -03:00 |
| Rosario Oddanchatram | India Standard Time | -08:30 |
| Rosario Odeceixe | Western European Time | -03:00 |
| Rosario Odense | Central European Time | -04:00 |
| Rosario Oka | Eastern Time | 02:00 |
| Rosario Ojai | Pacific Time | 05:00 |
| Rosario Ohio | Eastern Time | 02:00 |
| Rosario Oia | Eastern European Time | -05:00 |
| Rosario Ohain | Central European Time | -04:00 |
| Rosario Ogunquit | Eastern Time | 02:00 |
| Rosario Officer | Eastern Australia Time | -14:00 |
| Rosario Ogmore Vale | United Kingdom Time | -03:00 |
| Rosario Órgiva | Central European Time | -04:00 |
| Rosario Orion charter Township | Eastern Time | 02:00 |
| Rosario Orleans | Eastern Time | 02:00 |
| Rosario Orland | Pacific Time | 05:00 |
| Rosario Orangeburg | Eastern Time | 02:00 |
| Rosario Orange Park | Eastern Time | 02:00 |
| Rosario Omar | Philippine Time | -11:00 |
| Rosario Omerga | India Standard Time | -08:30 |
| Rosario Olympic Valley | Pacific Time | 05:00 |
| Rosario Ólvega | Central European Time | -04:00 |
| Rosario Ollantaytambo | Peru Time | 02:00 |
| Rosario Ollioules | Central European Time | -04:00 |
| Rosario Opatija | Central European Time | -04:00 |
| Rosario Oostkapelle | Central European Time | -04:00 |
| Rosario Opfikon | Central European Time | -04:00 |
| Rosario Ooltewah | Eastern Time | 02:00 |
| Rosario Oosterbeek | Central European Time | -04:00 |
| Rosario Onești | Eastern European Time | -05:00 |
| Rosario Onhaye | Central European Time | -04:00 |
| Rosario Ondara | Central European Time | -04:00 |
| Rosario Nurpur | India Standard Time | -08:30 |
| Rosario Nuremberg | Central European Time | -04:00 |
| Rosario Ñuñoa | Chile Time | 00:00 |
| Rosario Numana | Central European Time | -04:00 |
| Rosario Nyack | Eastern Time | 02:00 |
| Rosario Nyah | Eastern Australia Time | -14:00 |
| Rosario Nyaung-U | Myanmar Time | -09:30 |
| Rosario Nyaungshwe | Myanmar Time | -09:30 |
| Rosario Oak Hill | Eastern Time | 02:00 |
| Rosario Oak Bluffs | Eastern Time | 02:00 |
| Rosario Oak Brook | Central Time | 03:00 |
| Rosario Oakdale | United Kingdom Time | -03:00 |
| Rosario Oakdale | Pacific Time | 05:00 |
| Rosario Oakham | United Kingdom Time | -03:00 |