The dry season from December through April is the best time to visit Tayrona. The trails are dry, the sea is calmer and safer for swimming, and the sky is clear. January and February are peak months and the park gets crowded — book accommodation well in advance and consider arriving on a weekday.
The park closes entirely for several weeks each February as part of an Indigenous-led restoration period, a closure that is respected and enforced. Check the Parques Nacionales website for exact dates, as they vary year to year.
The rainy season from May through November brings daily afternoon showers that make the forest trails slippery and sometimes impassable. The sea is rougher and swimming more dangerous. June and July see some drier weather as a mid-year dry season briefly arrives. The park is least crowded in rainy season, which has its appeal if you're prepared for the conditions.