Weather in Zanzibar in December

Shoulder season. December sits in between. You will get good days and you will lose some. You should expect rain on 19 days of the month, which is more days wet than dry.

December ranks 11 of 12 — near the bottom of Zanzibar's year. July is the month that works, and the swing between the two is 42 points, which is a different holiday rather than a slightly better one.

This is persistent light rain rather than storms: 19 wet days but only 2 heavy ones. It rarely cancels anything outright, and it rarely fully clears either. A jacket beats an umbrella. Pack for 29.7 °C days and 27.2 °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: 11 days top 30 °C — hot spells arrive, but they break; the day barely swings — 2.4 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 31.1 °C and the coldest night fell to 26.1 °C, and the wettest single day dropped 34 mm — roughly 37% of the month's rain in one day.

December is moderately variable: 22 mm in the driest year against 196 mm in the wettest, around an average of 92 mm. Roughly two Decembers in three land near that average, and the third does something else entirely.

Wind is light at 15.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 76%, high enough to notice on the warm days without dominating them.

How December sits in the year

Temperatures hold steady either side: 29.3 °C in November, 29.7 here, 29.5 in January. Nothing about the timing within the month matters much. Rain is the thing that moves: January brings 7 days less of it, so pushing the dates later buys drier weather.

Daylight in December

Zanzibar sits close enough to the equator that daylight barely moves all year — 12.5 hours in December, against a range of just 0.7 hours across the whole calendar. Sunrise and sunset land at roughly the same time whenever you come.

Sea temperature

The sea sits at about 28.7 °C in December — warm enough that the water offers no relief from the heat. The sea peaks at 29.5 °C in March and bottoms out at 25.6 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

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

December in Zanzibar versus nearby

If Zanzibar is one option among several, the nearby comparison is worth making. Dar es Salaam is close enough to be a coin toss — within a degree on temperature, 3 days more rain. Mombasa is the weaker option in December — 4.4 °C warmer, 4 days less rain.

So: December is a compromise. July is 39 points better and is what Zanzibar is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Zanzibar

See all twelve months in Zanzibar, or where else to go in December.