Weather in Mombasa in September

How September compares

September is the 9th warmest month of the year in Mombasa and ranks 59th of 134 destinations we compare for September - see where else is hot in September. Against London's average high of 18.6°C in September, Mombasa is 9.0°C warmer by day and 11.5°C warmer at night.

Daytime and night-time in September

The typical September day in Mombasa peaks at 27.6°C, but that is an average: the warmest 10% of days reach 28.7°C or more. About 100% of days top 25°C and 1 in 500 pass 30°C. Nights average 22.7°C; one night in ten drops to 21.8°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 30.7°C (2008-09-21) and the coldest night 18.5°C (1996-09-24).

Rain in September

Wet (more than 8 rainy days): about 15 days with 1 mm or more, 45 mm in total. Year to year it varies a lot - the wettest September was 2018 with 120 mm, the driest 2001 with 9 mm. Humidity averages 78%.

Sea temperature in September

The sea averages 25.6°C - warm enough to swim (22°c+). Depending on the year it ranges from 25.3°C to 26.1°C. For the warmest sea here, come in April (28.8°C).

Sunshine and daylight

Around 6.5 hours of sunshine a day (estimated from cloud cover), 12.0 hours of daylight: the sun rises about 06:14 and sets about 18:19 local time in mid-September. Average cloud cover is 46%.

Is September a good time to visit Mombasa?

It is a reasonable choice: hot days but expect showers. The best months for Mombasa on our scoring are February, January, September; months averaging 25°C or more: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.

Hot enough for a beach holiday, with warm evenings

Average highs of 27.6°C make September hot without the average daytime temperature reaching 30°C. Humidity of 78% is the catch: even temperatures that look manageable can feel sticky, especially when you are active. Keep strenuous outdoor plans away from midday and favour loose, breathable clothing over heavy fabrics. With average night lows of 22.7°C, evenings offer only a modest cool-down, so do not pack as though you will need a typical British September wardrobe. A room with effective cooling is a sensible priority if warm nights affect your sleep. This weather suits travellers who want sustained warmth more than those who prefer crisp evenings.

Warm sea, but leave room for rain

The sea averages 25.6°C, making swimming a clear reason to choose September. That warmth is paired with a meaningful chance of wet weather: about 15 days receive measurable rain, so a completely dry holiday is not a sensible expectation. The figures do not mean those days are wet throughout, but they also do not justify assuming rain will conveniently fall outside your beach time. Keep outdoor plans movable, pack a lightweight waterproof and have something to do indoors when rain interrupts. September suits someone happy to work around changing weather for warm water and hot days; it is less convincing if uninterrupted sunshine is your main requirement.