Identifying Heat Hotspots: How Municipalities Find the Critical Locations

In short. A heat hotspot is not simply the hottest point on the map, but the place where high heat exposure and sensitive use coincide. A blazing hot industrial roof with no people is less critical than a moderately warm but heavily used square in front of a care home. Identifying hotspots therefore means overlaying temperature data with land use and vulnerability.

Why this matters for your municipality. Budgets for heat adaptation are limited. Distributing measures evenly wastes impact; concentrating them at critical locations achieves more with the same resources. Identifying hotspots is the step that turns a general heat map into a concrete list of priorities, and thus makes decisions in the council justifiable.

What makes a place a heat hotspot?

Three factors together: thermal exposure (daytime and, in particular, night-time values), the intensity of use (how many people spend time there) and the vulnerability of use (care home, daycare centre, hospital, senior citizens' meeting place, heavily frequented square). Only the combination produces urgency. A place can be very hot yet uncritical if no one is there, and vice versa.

How do you go about identifying them?

A multi-step approach has proven effective. First: record thermal exposure spatially, for instance via a heat map. Second: add the locations of vulnerable facilities and heavily used public spaces. Third: overlay both layers and mark the places where they coincide. Fourth: verify using local knowledge, the data shows candidates, and professional judgement confirms or rejects them. This produces a reliable, traceable list.

What data do you need for this?

On the exposure side: thermal data from satellites, climate models or measurements, ideally including night-time values. On the usage side: locations of care facilities, daycare centres, schools, hospitals, senior citizens' meeting places, as well as heavily frequented squares, stops and paths. Much of this is already available within the administration but is rarely brought together. This combination is the actual work; the raw data alone is not enough.

The honest limitation. A hotspot analysis is only as good as its data. If current location data is missing or the heat map is coarse, the result remains coarse. In addition, no analysis replaces an on-site inspection: microclimate, shade and actual use are not always evident in the data. Knowing your hotspots is the beginning of prioritisation, not its end.

When KomAdapt is worthwhile. Overlaying thermal exposure with vulnerable land use is exactly the task that KomAdapt's risk and exposure analysis was built for, as was done for the heat maps for the town of Meinerzhagen. Instead of manually combining datasets, you receive an overlaid view from which the critical locations and a well-founded order of priorities can be derived.

_Is the hottest point in the city automatically the most important?_ No. The hottest point can be an industrial or traffic area with no one present. A place only becomes critical through the combination of heat exposure and sensitive use. _Is a heat map enough to find hotspots?_ A heat map is the basis but is not sufficient on its own. Only overlaying it with land use and facility data turns the map into a hotspot analysis. _How often should hotspots be updated?_ Whenever the data basis or urban structure changes, for example after construction projects, new facilities or implemented measures. An annual review is sufficient in many municipalities. _Can small municipalities determine hotspots without a large budget?_ Yes. Even with limited resources, a rough overlay can be created from an available heat map and known facility locations. The benefit lies in the systematic approach.

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