I can only speak on Ghana from personal experience, but you can find weed. As a tourist you likely to either get finessed or get served some reggie but it's not like it's not there. The main difference is cultural, most people over there think weed is for lowlifes. Not to mention Ghana and most African countries stick to the "It takes a village" mindset. So it's harder for the young people to try it cause if anybody from your neighborhood sees you doing that shyt you catching an ass whooping from them and your parents after they tell them.