Maui enjoys warm weather year-round, but April-May and September-October (shoulder seasons) offer the best combination of good weather, lower hotel rates, and thinner crowds, avoiding both the winter holiday surge and summer school-break peak. December through March is peak season for whale watching, when humpback whales fill the channel between Maui, Lanai, and Molokai, but it also brings the highest prices and biggest crowds, plus occasional heavy surf on north-facing shores. Summer (June-August) is hot and dry with calm seas, ideal for snorkeling and Road to Hana drives. Winter brings more rain to the east side and Upcountry, so West and South Maui's beaches stay drier and sunnier.