In general, when booking your flight to Porto Alegre, September is the cheapest month on average.
Most flyers found that booking flight tickets 60 days in advance of their planned departure date is, on average, the best time to get cheap flights to Porto Alegre.
From most locations, the cheapest flights to Porto Alegre are found on a Tuesday. Booking a Sunday departure is usually the most expensive.
Generally, when visiting Porto Alegre, midday flights represent the best value. afternoon flights are likely to have higher prices.