The Gran Sabana has two seasons: wet (May to November) and dry (December to April). The dry season is the easier time to travel — roads are passable, treks are less muddy, and the long stretches of unpaved track to places like Kavanayén are reliable. The trade-off is that waterfalls are at their thinnest.
The wet season turns the savanna brilliant green and brings the cascades to full force. Roraima is climbable year-round, but trekkers who go in the wet season come down soaked. Late December through March is the most comfortable window; January and February are the driest.
Temperatures are mild for the tropics — 18–28°C at plateau level — and cool at night, particularly on top of Roraima where it can drop to near freezing. Bring layers.