Bissau month by month — at a glance
Hover each month for the summary. Click to pin it.
01 Three months at zero
Key moments at a glance
0.2 mm, 248 hours of sun and nights at 19.4 °C. No rain and no swelter.
A mean low of 18.3 °C, the calendar's lowest, with 0.1 mm.
279 hours of sun and not a drop, but the year's highest mean high.
467.7 mm and 24.1 rain days: the wettest month of the calendar.
The full series shows the step. December 0.2 millimetres; January 0.1; February 0.0; March 0.0; April 0.0; May 10.6. And from there: June 139.9; July 371.0; August 467.7; September 364.4; October 166.7; November 10.9. The year totals around 1,532 millimetres over close to a hundred rain days.
Sunshine, by contrast, does not collapse as much as you might expect. The year totals about 2,707 hours and the minimum, in August, is 155: considerably more than other capitals on this coast record at the height of the season. It rains hard here, but it also clears.
02 Heat without rain
What really sets Bissau's dry season apart from other capitals in the region is the thermometer. In February, March and April the mean high is 35.2, 36.0 and 35.3 degrees: they are the three hottest months of the year, and they coincide exactly with the three that record no rain.
A mean high of thirty-six degrees and zero millimetres of rain in the same month. The dry air makes it bearable, but the number is what it is.
The compensation is at night. In the dry half of the year the mean low drops to 18.3 degrees in January, 19.0 in February and 19.4 in December, while in August it stays at 23.3 with maximum humidity. The gap between day and night reaches fifteen or sixteen degrees in March, and seven in August.
03 And then, four hundred and sixty-seven
The other extreme arrives fast. From May's 10.6 millimetres you go to 139.9 in June, and from there to 371.0 in July and 467.7 in August. Between June and October ninety-nine per cent of the year's water falls, and in August it rains on 24.1 days out of 31.
On the ground that means two things. First: the earth tracks of the interior and the islands become very difficult, and journeys that take two hours in January may stop being possible at all. Second: boat trips across the estuary and out to the archipelago depend on the state of the sea and get complicated.
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04 Which month to pick
December and January are the two best months, and for one specific reason: they combine zero rain with the coolest nights of the year, mean lows of 19.4 and 18.3 degrees, and 248 hours of sunshine each. It is the only part of the calendar where you do not have to choose between staying dry and being comfortable.
February, March and April still bring no rain, but the heat climbs: mean highs of 35.2, 36.0 and 35.3 degrees. They are perfectly viable months if you accept organising the day around the morning and the late afternoon. November is the other door, at 10.9 millimetres and with the countryside still green from the season.
And June to September is worth thinking hard about. It is not just that between 140 and 468 millimetres fall each month: it is that it rains on between twelve and twenty-four days out of thirty, and everything that makes this country interesting — the islands, the estuary, the inland tracks — depends on being able to move.
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