Zanzibar pairs Stone Town's UNESCO Swahili-Arab old quarter and the House of Wonders, the spice plantations of the interior, the long beach at Nungwi and Kendwa in the north, and Mafia Island's whale-shark waters in the south.
Cool dry season with Stone Town walking pleasant, Sauti za Busara music festival in early February aside, and Mafia Island whale sharks year-round but visibility at peak.
Short dry season with sea calmest, Zanzibar International Film Festival in mid-July aside, and the Christmas through New Year window at peak resort demand.
Long rains with afternoon storms, lower rates across resorts, and Stone Town's spice tours running between showers with the rains greening up the interior.
Short rains with afternoon storms manageable, sea returning to calm, and the dry-season buildup beginning across Stone Town and the north-coast beaches.