Spring and autumn are the best seasons. April and May bring wildflowers in the Maremma and good birdwatching in the lagoon, with warm days and mild evenings. September and October are excellent for swimming — the sea is still warm — and for the bottarga harvest in the lagoon.
July and August are hot and busy: the beaches fill with Roman weekenders, restaurants need reservations, and prices on Monte Argentario climb. Winter is quiet but rewarding for birders — this is when the greater flamingos are in residence on the lagoon in the largest numbers.