May weather and when to go
Officially May still continues the long rainy season (maisika) however, in recent years May has been surprisingly dry so it is really difficult to predict. If the rains do persist they are unlikely to perpetuate the whole day on the mainland. The chart above shows the averages for the Serengeti throughout the month and the comparative average rainfall in Zanzibar
On Zanzibar however, it is possible for rains to pour every day for weeks on end, again making this time of year less favourable. You can see from the table below the average monthly rainfall for Zanzibar is 261mm. That is the most of any month in Tanzania!
The eastern side of Zanzibar remains relatively cheap before the main dry season starts and if you’re lucky you could receive consecutive dry, sunny days but this may be taking a risk.