Het weer in Fernando de Noronha (Noronha) in september

September is the month divers name for Noronha, because underwater visibility is at its best - 30 metres on average across the island's twenty-odd sites and up to 50 at some of them, with turtles, tuna, jacks, barracuda, groupers and jewfish. The seasonal logic behind it: the rains run March to June, and December to March is the stormy stretch that makes the surfing season, so September sits in the quiet gap. Our row's 10.7 precipitation days over just 22.8mm is about two millimetres a day, showers rather than weather. What it does carry is wind, 32.5 kph of south-east trade. The record: 29.9C days reading as 32C, 24.9C nights, humidity 79 percent, 11.4 hours of sun and a 27C sea.

Regulars are specific this falls within the March-to-July rainy season here, though real rain typically means a strong but short tropical-style shower rather than an all-day soak, one visitor's full week here logging just a single day of rain that barely affected their plans. Our row backs that warm, genuinely wet read, 28.9C reading as a hot 31C, over 24.6C nights feeling 26C, with a substantial 100.7mm of rain across 19 days and a real 30.9 kph wind. Regulars are consistent temperatures stay comfortable in the 25 to 30C range even during an actual shower, this remaining a genuinely great choice for the month despite technically falling in the wet season. The sea sits at a bath-warm 27.5C. The record: 10.8 hours of sun, humidity 80 percent and AQI 51.

December sits opposite the island's rainy stretch, which regulars place from March to July, so this is Brazilian summer at its driest and the season for turtle hatchlings on the beaches. Our row backs the calm half of the year - 44mm across 11.4 days, modest next to the wet months - though air is 30.7C reading as 34C at 80.9 percent humidity, over 25.8C nights and a 27.6C sea. The permit system is the one fact every visitor needs regardless of season: the national-park beaches like Sueste and Sancho charge an entry fee, and it is worth arranging before arrival rather than at the gate. Their warning about the wet months is blunt - when it does rain here there is genuinely nothing to do and the roads can become unusable - which is exactly why December is preferred. The record: 11.4 hours of sun, a 28.6 kph wind and AQI 36.

August opens the drier half of the year here and divers name it and September as the two months to come for, because the underwater visibility is at its best - the figure they quote for these waters runs up to fifty metres across twenty-one sites between fourteen and forty-five metres deep. Our row reads the dryness the way these tropical islands usually do: 37.6mm spread over 13.6 precipitation days is under three millimetres each, so showers rather than rain. The other figure to plan around is wind, at 32.3 kph, which is what keeps 29.3C days feeling like 30C rather than worse. The record: 24.6C nights, humidity 79 percent, 11.1 hours of sun, a 27C sea and AQI 54.

October is the tail of Noronha's better half for diving. The window the forum gives runs roughly April through October - visibility routinely around 30 metres and sometimes closer to 50, with turtles, tuna, jacks, barracuda and big groupers - after which December to March turns stormier and the island becomes a surfing proposition instead. October's other feature is the wind, 31.3 kph on our row, which is most of why a 30C day feels like 33 rather than worse. The rain here is scattered rather than seasonal this month: 7.8 precipitation days carrying just 18mm between them. The record: 25.2C nights, humidity 79 percent, 11.5 hours of sun and a 27.4C sea.