Mayotte seasonal outlook: normal rain, hotter days ahead

Météo-France Mayotte issued its seasonal outlook for the November-December-January 2026/2027 quarter on 4 November 2026, and the operational message is straightforward. Rainfall totals over the archipelago are expected to run close to normal. Average temperatures, by contrast, are forecast to remain well above seasonal norms. The bulletin covers the quarter that marks the start of the rainy season across much of the region.

The regional picture the service sets out is one of systems arriving on schedule. A monsoon flow progresses southward, reaching 10 degrees south latitude, accompanied by the rain-bearing systems associated with the ITCZ and merging with the humid Congolese air mass. In the southern part of the basin, the Mascarene anticyclone shifts toward the southeast, steering a wetter trade wind flow over the Mascarenes and Madagascar. For the quarter ahead, the numerical models show a low-level circulation configuration consistent with what a combination of El Nino and a negative SIOD would produce. Meanwhile, the influence of the IOD tends to fade during this period, and the flow anomaly helps encourage the monsoon in its southward progression across the basin and over the northern part of the continent.

Behind the local forecast sits a set of oceanic indicators the service tracks closely. In the equatorial Pacific, all forecasts agree on a scenario of ENSO growth in its positive phase, with El Nino set to reach its maximum by the end of the year. The atmospheric feedback weakens slightly but holds through the coming quarter, sustained by a low-level flow that organises from east to west around the equator before turning south-southeast.

In the Indian Ocean, Mayotte itself sits under the influence of a low-level wind anomaly coming from the southwest. The IOD is expected to begin declining after peaking during the October-November-December quarter. The SIOD should reach its minimum in a negative phase at the end of the year, though the bulletin is candid about the limits of that projection: uncertainty around this parameter remains high. The service also flags a recurring performance issue with the models, noting that during previous El Nino episodes the amplitude of the SIOD has almost always been underestimated.

That kind of self-assessment is where the practical value of the bulletin lies. A seasonal forecast is only as useful as its stated reliability, and Météo-France Mayotte separates what the models handle with confidence from what they do not. The Pacific ENSO scenario is presented as a point of agreement across all forecasts, while the SIOD carries an explicit warning about uncertainty and a documented history of model underestimation. For anyone relying on the outlook to plan around the coming quarter, the distinction matters: the rainfall signal for Mayotte is near normal, the temperature signal is firmly above normal, and the confidence attached to the underlying drivers varies considerably.

The bulletin frames the NDJ quarter as the onset of the rainy season across the region, both on the continental portion and on the islands. Within that framework, the forecast for Mayotte is one of continuity rather than disruption. A monsoon flow advances on schedule. An anticyclone repositions to push wetter trades westward. And the local rainfall outlook does not depart from seasonal norms even as temperatures stay elevated.

What the October 2026 edition ultimately delivers is a working picture of the season ahead, built from model output the service is willing to qualify where qualification is due. The near-normal rainfall projection and the above-normal temperature projection stand as the headline outputs, with the oceanic context, and its acknowledged uncertainties, explaining how that picture was assembled. Whether the SIOD behaves as projected, given its history of being underestimated, is the open question hanging over the rest of the forecast.