in fact, april is considered by many one of the very best months to enjoy rio de janeiro as a whole - as the temperatures are never excessive and the beaches almost never crowded during week-days.

this link gives access to detailed  daily, weekly, and monthly weather forecasts, as well as sunrise and sunset times.

this wundermap shows current temperatures for the various districts in rio de janeiro - the map can also be used to see precipitation, dew point, humidity and visibility.