For Zanzibar :
No gale warning.
For the night from Wednesday to Thursday S wind force 4 continuing all night. Gusts reaching 19 knots in the middle of the night.
Slight sea. Low, short swell from ESE. Excellent visibility. Daytime of Thursday 22 may : The atmosphere will remain unstable.
Very cloudy with risk of thunderstorms in the morning, sun and storm clouds in the afternoon. Showers all day. In the evening, storms developing.
Showers. SSW force 4 in the morning becoming S force 5 in the middle of the day. Gusts reaching 21 knots in the evening. Slight sea becoming moderate in the middle of the day. Low, short swell from ESE. Excellent visibility.