This is the mildest summer we’ll still get to experience
The June heatwave is behind us. During that period, more than 20,000 people died across Europe due to the extreme heat. “European homes, workplaces, and schools were not built for these temperatures,” says the Director-General of the World Health Organization (WHO). The next regional heatwave is already on its way, this coming weekend. But how do you make sure every resident has a cool place nearby, especially on the hottest days?
Third regional heatwave of 2026 arriving this weekend
In the Netherlands, around 480 people died as a result of the June heatwave. After a slightly calmer period, temperatures are already rising quickly again this week. From Thursday, the south of the country could see tropical heat once more, with the warmth persisting into next week. There’s a good chance this weekend will mark the third regional heatwave of 2026.
“The heatwave that used to occur only once a generation now happens almost every year,” warns Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization (WHO). We can no longer deny this problem. The question is no longer whether the next heatwave will come, but how well prepared we are for it.
Why some feel it harder than others
Heat risks often arise from multiple factors at once. In a paved, stony neighborhood with little greenery, it can be 4 to 7 degrees warmer than in a green neighborhood. Some homes heat up quickly, such as through-sun (doorzon) houses. In addition, some people are extra vulnerable — for example, older adults who feel less thirst or have limited social contact.
The Heat Menu
Because the risk of extreme heat in the Netherlands is increasing, the Heat Menu (Menukaart Hitte) was developed in 2022. This menu gives municipalities an at-a-glance overview of the steps they can take to prepare for heat, with concrete choices in the areas of health, buildings, and the living environment.
This approach is built around three components:
- Health: protecting vulnerable residents
- Buildings: making homes and buildings heat-resistant
- Area: designing public space for cooling
The brochure, the guidance document Integrated Heat Action Plan, and the Heat Menu were developed on behalf of the Ministry of Housing and Spatial Planning (VRO) and RVO, in close collaboration with the Dutch Climate Alliance (Klimaatverbond Nederland), TAUW, and &flux. In this article, from &flux, we zoom in on that third component: what can you do in an area to create cool spots and cool routes?
Trees: the most effective and closest-to-home solution
The most effective form of cooling is surprisingly close to home: trees. A mature tree can lower the local perceived temperature by several degrees. Large tree canopies provide shade, evaporation, and a more pleasant microclimate. Combine that with water, permeable paving, and inviting places to linger, and a paved square turns into a place where people can safely spend time even during extreme heat.
This investment is especially needed in densely built neighborhoods, where temperatures rise the highest and residents often have fewer options to seek out cooling themselves. Climate adaptation is therefore not just a technical challenge, but also a matter of climate justice.
Besides greening public space — something we at &flux are working hard on through the Green In and Around the City (GIOS) program — heat calls for a broader approach: buildings that are better equipped to withstand high temperatures, shaded walking and cycling routes, more water in the city, and homes that don’t turn into ovens the moment the thermometer climbs above thirty degrees. Just as important: every resident should have a cool place nearby.
Green oasis squares
From that idea comes the concept of green oasis squares: publicly accessible, green, cool meeting places in the heart of towns and cities. Alongside the cooling spots already being set up more and more often — in supermarkets, libraries, and community centers — natural cooling spots need to emerge as well. Places where large tree canopies play the leading role. Where people can rest, meet each other, and find relief on hot days. Recognizable places that not only contribute to health and livability, but also show that a municipality takes heat seriously.
We are working together on developing a method to create these green oasis squares in municipalities. The concept goes beyond simply adding greenery. It helps municipalities give administrative priority to heat, organize funding, and introduce a recognizable quality label. Just as a Johan Cruijff Court is instantly recognizable anywhere in the Netherlands, these green oasis squares could grow into the symbol for healthy, climate-resilient public space.
Breaking the cycle
With every heatwave, we see the same picture: improvised sun shading, empty streets, schools closing, and vulnerable residents barely able to find any relief — along with a rise in preventable heat-related deaths. Less visible are the drop in labor productivity and the increase in aggression, partly caused by poorer sleep. Then attention fades again, until the next heatwave arrives. That cycle needs to be broken. Because this is probably the coolest summer we’ll still get to experience.
That calls for choices that go beyond emergency measures during a heatwave. It calls for cities designed for a warmer climate. For investment in trees, water, and shade. It calls for action from policymakers who take heat and cooling seriously.
Green oasis squares can be a powerful and visible tool in that shift. Not because a single cool spot solves the problem, but because they can set a movement in motion: a movement in which every municipality has the ambition to offer residents a safe, cool place, especially on the hottest days of the year. Because if extreme heat becomes the new normal, then cooling needs to become the new normal too.
