The best time to visit Watamu is July to October, when the long dry season delivers clear skies, calm seas ideal for snorkelling and diving, and reliable wildlife sightings. Visibility in the marine park regularly exceeds 20 m in August and September.
January and February are equally rewarding — hot, sunny, and calm, with the bonus of peak big-game fishing season (marlin and sailfish are most abundant October–March). These months are also good for whale shark encounters offshore.
March to June brings the long rains (kaskazi season). Watamu receives heavy showers, particularly April and May, which can affect sea conditions and visibility. However, this is sea turtle nesting season (March–July), making it worthwhile for conservation enthusiasts despite the wetter weather. Rates drop significantly and the beach is quieter.
July to August is peak season and the busiest period, especially with Kenyan and European school-holiday visitors. Book accommodation early. The short rains (vuli) fall October–November but are lighter and shorter than the long rains, rarely disrupting a full week's itinerary.