Coole Straßen — Vienna's Temporary Street-Cooling Pilot Against Urban Heat Islands

In 2019, the City of Vienna piloted „Coole Straßen“ (Cool Streets) on three streets in the city's hottest micro-climate zones — Fasanviertel (3rd district), around Columbusgasse (10th district) and around Hasnerstraße (16th district) — identified by the city's urban heat-island mapping. Streets were closed to car traffic for the summer and fitted with seating, shade sails, fog-mist showers and partial depaving („unsealing“) of asphalt surfaces.
The city's own climate monitoring found ambient street temperature fell by up to 5°C where fog showers, added water features and surface unsealing were combined, according to Vienna's Presse-Service archive report of 19 May 2020. A parallel social-science evaluation of the 2019 pilot found 92% of surveyed residents wanted the measure repeated; a follow-up representative survey of 806 Viennese in April 2020 found 70% viewed Coole Straßen positively.
Based on this evidence the programme scaled from 3 streets (2019) to 22 streets (2020), run by the Vienna Mobility Agency (Mobilitätsagentur Wien) under the responsible city councillor's office. When the temporary programme ended in autumn 2021, four sites — the strongest performers — were converted into permanent „Coole Straßen Plus“ with lasting shade, greenery and unsealed surfaces, rather than being reverted to standard streets.
The measured cooling effect is highly context-dependent: independent reporting (Street Experiments / SET) notes the largest temperature drops occurred only where misting, water and unsealing were combined, and that the programme functioned primarily as a temporary space-reallocation pilot rather than a permanent green-infrastructure retrofit for most of the 22 sites — most reverted to ordinary streets after 2021.

Read the full analysis: https://presse.wien.gv.at/2020/05/19/hebein-22-coole-strassen-bringen-abkuehlung-und-platz-fuer-wiens-hitzepole