PARIS, France — A string of record-smashing summers is forcing travelers, tour operators and destination managers in Paris and around the world to rethink when and where to vacation. From Andalusia’s 45 °C afternoons to emergency fire evacuations in California and Greece, extreme heat is no longer a rarity—it is the backdrop to peak season.

Travelers heading to Spain’s white-washed villages and beach-rimmed costas this week may want to build a longer lunch break into their itineraries. Seville and much of Andalusia are reporting peak temperatures approaching 45 C, a level that Spanish meteorologists say is a new regional record. Local authorities have activated heat-health plans and are pleading with residents and visitors alike to stay out of the sun during the hottest stretch of the day.