A cloud of Saharan dust is set to drift over France starting this Sunday, July 12, 2026, with a peak expected between Sunday evening and Monday morning. In Paris (75) and the seven other departments of Île-de-France, namely Seine-et-Marne (77), Yvelines (78), Essonne (91), Hauts-de-Seine (92), Seine-Saint-Denis (93), Val-de-Marne (94) and Val-d'Oise (95), the red heatwave alert remains in place on July 12 and 13. In short, the sand arrives at the worst possible moment.
All of this is unfolding far from us, off the coast of Portugal. A high-altitude anomaly parked near the Iberian Peninsula is speeding up the southerly flow and acts as a motor: it channels the air mass that rises from North Africa toward Western Europe.
Desert dust then travels thousands of kilometres. It first blankets Spain, crosses the Pyrenees, reaches Occitanie and Nouvelle-Aquitaine, then covers the western half of the country before reaching the Paris basin.
The result is obvious to the eye: a hazy, almost milky sky, and sunsets tinted with orange. The downside is just as familiar: if a rain shower comes through, car exteriors pick up a thick film of deposits, and with water restrictions in place, rinsing them off is difficult.
It's the least understood—and the most punishing. On a typical heatwave night, the ground and façades release the heat stored during the day, making the thermometer slow to fall.
With Sahara dust suspended in the air, this heat stays trapped in the lower levels of the atmosphere. The aerosols curb radiative cooling — in other words, the loss of heat from the ground and the air overnight. A kind of fine blanket laid over our rooftops.
“The influence of dust as aerosols helps keep nightly low temperatures higher. On Monday and Tuesday, the lows could range from 22 to 26°C across nearly the entire country, except for the far north,” says meteorologist Yann Amice for actu.fr. Météo-France even forecasts 27°C in Paris during the Monday-to-Tuesday night.
The phenomenon is not unprecedented. At the end of June, during the previous heat wave, the CNRS had already noted that a strong concentration of desert dust helped sustain nighttime temperatures that stayed very high for several consecutive days, as recalled by Le Parisien.
Dust plumes are set to move in from Monday, July 13, 2026, and are expected to persist until Thursday across the western half of the country, and through Friday in the east. In Île-de-France, the heatwave should begin to ease its grip around July 15–16, as more oceanic air arrives.
Until then, the nights across Île-de-France are set to be tough. Early Sunday morning, at 5 a.m., it was still 23°C at Paris-Montsouris and 23.6°C in Orly. The body hardly gets a chance to recover, and that is precisely what is worrying health authorities.
These dust particles also carry fine particulates, which can degrade air quality. People with asthma, allergies, or respiratory conditions would do well to follow Airparif's daily forecasts for the Île-de-France region and to scale back outdoor exercise.
As for the rest, the guidance stays the same as at the outset of this episode: stay hydrated, close shutters and windows during the day, ventilate at night whenever the temperature allows, cool off several times a day, and check in on elderly or isolated people. The Santé publique France platform outlines all the recommended precautions. Also to read: our full briefing on the red heatwave alert in Île-de-France.
Dates and Opening Time
From July 12, 2026 to July 13, 2026
