Weather in March

Hello, Ill be visiting Brazil by end of March and I was hoping to make the most of the beautiful beaches. While searching online it says that the weather its still hot but not as humid, with the occasional rain showers, however in this sub I noticed many people warning tourists for summer storms. Im not expecting it to be sunny all days, but there’s still some hope of enjoying the beaches right? Going to Rio, Ilha Grande, Paraty and Sao Paulo