Javier Recio held a lawn chair like a parasol over his mother’s head. The two had given up on sitting outside and were walking home through one of the least green, and most sweltering, neighborhoods of Seville. A pharmacy sign posted a temperature above 100 degrees Fahrenheit, and a drinking fountain trickled scorching water.

“We need to do something,” said Mr. Recio, 48.

In August, deadly wildfires forced the evacuation of thousands of people in northern and southern Spain and damaged a Roman-era mining site on the UNESCO world heritage list. Temperatures cracked 111 degrees Fahrenheit (44 Celsius), and Prime Minister Pedro Sánchez warned the country, “We’re at extreme risk.”

Throughout this long and miserable summer, Seville, in the country’s south, has become a furnace of southern Europe. Its residents hope for some relief from increasingly frequent and intense heat waves that threaten the most vulnerable. But the city, like everywhere else, has no quick fix for the disastrous consequences of a warming planet and is hardly on the cusp of futuristic breakthrough. Plans for a single cooling bus stop are still in the works.

What the city does have is a deep history of sweating it out with common-sense coping mechanisms.

The traditional siesta is no accident. As places like Norway and Finland hit higher temperatures, an increasingly uncomfortable continent may find itself looking to Seville and other cities that have been living with the heat for centuries for ways to get through what feels like the perpetual inferno of summer.