published by the prefeitura da cidade do rio de janeiro and the instituto municipal de urbanismo pereira passos - ipp the map bacias e sub-bacias hidrográficas shows basins and sub-basins of metropolitan rio.

provided daily by the diretoria de hidrografia e navegação of the brazilian navy, this link opens a synoptic chart showing sea level pressure, this link opens a wavewatch chart, while a weather forecast can be seen on this link, and a forecast specifically for guanabara bay on this link.

cartas nauticas brasil makes detailed maps of the guanabara bay available for sale on this page.