Guyana has a tropical climate with temperatures staying between 25°C and 32°C year-round. The main variable is rain. There are two wet seasons — May to early August and late November to January — and two dry seasons, roughly February to April and September to October.
The dry seasons are the best time to visit, particularly for the interior. Roads (such as they are) become impassable in the wet season, rivers flood, and the risk of flight cancellations increases as small aircraft are grounded by low cloud and rain. If you are heading to the Rupununi or any remote interior destination, try to go during a dry season.
The one exception is Kaieteur Falls. The falls are most impressive during or just after the wet season, when the flow is at its maximum. The best combination is to visit just after the long wet season ends — late August or September — when the falls are still full but conditions for travel have improved.
Georgetown and the coast can be visited year-round and are less affected by the wet season than the interior.
For wildlife, the Rupununi dry season (September–November) concentrates animals around shrinking water sources, making it an excellent time for jaguar sightings and birding. Leatherback turtles nest on Shell Beach from March to August, peaking around May and June.
Carnival and Mashramani (Republic Day, February 23rd) bring celebrations to Georgetown and are worth timing a visit around if you enjoy street festivals.