The best time to visit Panama really depends on what you plan to do. If you intend to spend most of your time on the Pacific side, try December or January, when there’s generally little rain and the weather is pleasant. If you’re doing any serious hiking, this is also the most comfortable time to do it; the Darien Gap can be crossed only at this time. Bear in mind, however, that hotel prices and airfares are generally higher in the dry season (mid-December to mid-April). For planning purposes, be aware that Panama’s mountains can get very cold at night; be sure to bring warm clothing.
Some of Panama’s colorful festivals draw large crowds. If you like to party, try to be in Panama City or Las Tablas for Carnival, held each year on the weekend before Ash Wednesday. Hotel reservations during Carnival are a must and should be made well in advance.