Weather in Nairobi in September

Prime time. September is about as good as Nairobi gets. Highs average 28.4 °C, lows 13.4 °C, and rain falls on 6 days — nothing in the month is working against you.

September ranks 4 of 12 in Nairobi: past the worst of the year but short of July, which is the month to book if the dates are open.

Rain falls on only 6 days, so an itinerary with no wet-weather fallback is a reasonable risk. Pack for 28.4 °C days and 13.4 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 6 days top 30 °C — hot spells arrive, but they break; the day swings 15 °C from low to high, which means one bag has to cover both. Across the twenty years measured, the hottest September day reached 32.5 °C and the coldest night fell to 9.5 °C.

September is moderately variable: 5 mm in the driest year against 40 mm in the wettest, around an average of 20 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 11.4 km/h, so the temperature on the page is close to the temperature on your skin, and humidity is unremarkable at 59%.

How September sits in the year

Temperatures hold steady either side: 26.8 °C in August, 28.4 here, 28.6 in October. Nothing about the timing within the month matters much. Rain is the thing that moves: October brings 8 days more of it, so the earlier half of a flexible trip is the safer half.

Daylight in September

Nairobi sits close enough to the equator that daylight barely moves all year — 12.1 hours in September, against a range of just 0.2 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

An inland climate

Despite being inland, the year stays fairly even: 16.9 °C between the year's warmest afternoons and coldest nights. At 1684 m, altitude is doing as much work here as latitude: thinner air means fierce sun by day and heat that leaves the moment it sets. Within September itself the daily swing is 15 °C, so mornings and afternoons need different clothes.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself. September is the value pick for Nairobi: it scores within 10 points of July without carrying July's prices.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Nairobi versus nearby

If Nairobi is one option among several, the nearby comparison is worth making. Nakuru is the weaker option in September — 3.3 °C cooler, 12 days more rain. Kakamega is the weaker option in September — 3 °C cooler, 20 days more rain.

So: September works, with July the better month by 10 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Nairobi

See all twelve months in Nairobi, or where else to go in September.