Porto-Novo month by month — at a glance
Hover each month for the summary. Click to pin it.
01 Four stretches, not two
Key moments at a glance
16 mm in the whole month, at 27 °C. Twenty-three times less water than June.
44 mm and the year's coolest month, between two rainy seasons.
Over a quarter of the annual rain concentrated into four weeks.
The classification is tropical savanna, Aw on the Köppen scale, and the two documented wet seasons run March to July and September to October. Adding the twelve months, the annual total comes to around 1,325 millimetres.
The temperature, by contrast, barely moves: between 25 and 28 degrees all twelve months. Three degrees of range in total. Here the calendar is not set by the thermometer but by the rain gauge, which is the opposite of what happens at most destinations.
02 June: 370 millimetres
June is by a wide margin the month to dodge: 370 millimetres, more than a quarter of the year's water in four weeks. May precedes it with 215 and July follows with 129, so the May-to-July block takes 714 millimetres, more than half the annual total.
June: 370 millimetres. December: sixteen. The same city with twenty-three times more water on it.
03 The August pause
And here is the peculiarity almost nobody expects. August, in the middle of the northern summer and between two rainy seasons, delivers only 44 millimetres. It is also, along with July and September, the coolest month of the year, at 25 degrees.
That parenthesis is a real window: four weeks of respite between the May-to-July block and the September–October rebound. It is not as reliable as December — 44 millimetres is not zero — but it allows travel in a stretch of the calendar that on paper looks impossible.
.jpg?width=1200)
04 The good window
November to February, and within that stretch, December. The driest month of the year delivers 16 millimetres at a mean of 27 degrees; January follows with 23 and November opens the stretch with 52. That is four consecutive months below 60 millimetres, something the calendar does not repeat.
One note worth carrying: this is also the season when the harmattan blows, the dry wind off the interior that loads the air with fine dust and cuts visibility. It does not ruin the trip, but it explains why in December and January the horizon can look milky even without a cloud.
In short: come in December or January. If you cannot, August is the reasonable alternative and is also the coolest month. And avoid June above any other consideration: 370 millimetres on a flat city, 38 metres above sea level and pressed against a lagoon, is not a meteorological detail.
