the surf bus leaves from largo do machado every day at 7 am, 10 am,1 pm, and 4 pm. more details are posted on their webpage. 

this link shows praia de grumari on a wikimapia - the link as we present it is best seen using google chrome, as it might not open correctly with other browsers. on this link an early morning shot of the beach is posted daily, showing water conditions.

on this link, the instituto estadual do ambiente - inea, provides the suitability of several beaches, including praia de grumari.