Cameroon's southwest coast has two seasons. The dry season runs roughly from November to March: skies are clearer, the humidity drops to something manageable, and Mount Cameroon is more likely to be visible from the coast. This is the best time to visit, and the best window for attempting the mountain — good visibility and more stable conditions on the upper slopes. December to February is peak season, when the weather is most reliable.
The wet season, April to October, brings heavy rain — Limbe sits in one of the wettest parts of Africa, and annual rainfall can exceed 10,000mm. The mountain disappears into cloud for weeks at a time, the roads to Mile Six can flood briefly after downpours, and the general mugginess is enervating. That said, the Wildlife Centre and the Botanic Garden are perfectly enjoyable in the rain, and prices are lower. August is the wettest month.
Regardless of season, the rhythm of the week matters as much as the time of year. Limbe is a weekend escape for Douala residents, so Friday evening through Sunday is noticeably busier — noisier beach bars, fuller restaurants, more expensive rooms. If you want the quieter, more local version of the town, arrive on a Monday.