Thick dawn fog disrupts operations at São Paulo’s Congonhas and Guarulhos airports

Passengers travelling through Brazil’s largest city faced significant headaches on Saturday morning, 26 September 2026, when a dense blanket of fog reduced visibility below take-off and landing minima at both São Paulo-Congonhas (CGH) and São Paulo-Guarulhos (GRU). From 06:00 to 09:30 local time, air-traffic controllers placed both airports under low-visibility procedures, forcing airlines to divert inbound aircraft to Campinas-Viracopos and Rio’s Galeão, while dozens of domestic departures were held on the ground. LATAM Airlines said 12 of its early-morning rotations were canceled outright and a further 18 left with delays exceeding one hour. GOL and Azul reported similar figures. The knock-on effect rippled through Brazil’s trunk routes – especially the lucrative Rio–São Paulo shuttle – with Santos Dumont airport recording delays after aircraft were unable to depart São Paulo on schedule. Airport operators GRU Airport and Aena (which manages Congonhas) activated contingency plans, opening extra check-in positions and distributing water to stranded passengers. Meteorologists at the Brazilian Air Force’s DECEA explained that early-spring temperature inversions often trap humidity over the plateau and warned that similar conditions could recur over the next fortnight. The episode emphasises the importance of travel-risk monitoring for multinational firms with tight same-day schedules in Brazil’s financial capital. Mobility teams are advised to book morning meetings with caution, build slack into itineraries and remind employees to register for airline SMS alerts. Travellers connecting to onward international services out of GRU should factor in at least a three-hour buffer when fog is forecast. ANAC noted that the airports resumed normal visual operations by mid-morning and that no safety incidents were reported. Nevertheless, the authority reiterated its call for carriers to improve real-time passenger communications and reviewed de-icing and diversion protocols ahead of the Southern Hemisphere’s rainy season.