Burkina Faso has two seasons: dry and wet. The dry season runs from November to April, the rainy season from May to October. Within that simple framework, the differences are dramatic.
November to February is the best time to visit. Temperatures are warm but manageable — highs around 30-35C in the south, cooler at night. Skies are clear, roads are passable, and the landscape still has some green from the recent rains. December and January are the most comfortable months. The main drawback is the Harmattan, a dry wind from the Sahara that carries fine dust and can reduce visibility to a haze, particularly in December and January. If you have respiratory sensitivities, be prepared.
March to May is brutal. Temperatures regularly hit 40C and above, humidity starts to climb, and the landscape bakes. The hottest month is usually April. This is not a pleasant time to travel unless you have a specific reason to be here.
June to October is the rainy season. The rains green up the countryside beautifully and cool the air somewhat, but roads — especially unpaved ones in the south and west — can become impassable. Travel between towns gets harder and slower. The upside is that the landscape transforms: dry scrub becomes lush savanna, and birdlife peaks. September and October see the heaviest rains.
If you are timing a trip around events, FESPACO takes place in Ouagadougou in late February of odd-numbered years. The Semaine Nationale de la Culture (SNC) in Bobo-Dioulasso is a major arts and culture festival held every two years. Both are worth building a trip around.
Wildlife viewing at Nazinga Game Ranch is best in the dry season, particularly January to April, when animals congregate around waterholes and the vegetation thins enough to spot them easily.