Planning for the weather is a good way to make your trip to São Luís relaxing and enjoyable, especially when you’re splurging. The hottest months are usually October and September, with an average temperature of 27°C, while the coldest months are July and June, with an average of 27°C. The rainiest months in São Luís are April, March, February and May, with each month seeing an average of 522 mm of rainfall.