Kyrgyzstan's Heatwave Strategy: Watering Streets Creates 'Sauna Effect,' Says Ecologist

Authorities in Bishkek and Osh are resorting to watering streets and roads during heatwaves, a practice criticized by environmentalists as ineffective and potentially counterproductive. Instead of prioritizing the irrigation of green spaces, which would offer genuine cooling benefits, municipal services are focusing on asphalt surfaces.

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We analyzed the temperature indicators when we compiled the city's thermal map. The hottest period starts around July 15 and lasts until August 5-10. So, it's too early to relax – there are still two to three weeks of real heat ahead.

Ecologist and urbanist Dmitry Pereyaslavsky explains that spraying water on superheated asphalt, which can reach temperatures of 70 degrees Celsius or higher, creates a "sauna effect." While the asphalt surface might cool momentarily, the water quickly evaporates, significantly increasing air humidity. This heightened humidity makes the heat feel more oppressive, similar to the difference between a dry sauna and a humid Russian banya.

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In a dry sauna, the temperature can reach 120 degrees, but it's tolerated better. In a Russian banya, the temperature is lower – about 60 degrees, but high humidity makes the heat much harder to bear. A similar process happens in the city. When hot asphalt is watered, it effectively creates a steaming effect.

Pereyaslavsky points out that Kyrgyzstan is entering the peak of its summer heat, typically from mid-July to early August. He argues that the current approach of daytime street watering is a superficial measure. The water evaporates rapidly, the asphalt darkens and absorbs more heat, and the humidity rises, exacerbating the discomfort. He suggests that focusing on maintaining and expanding green areas would be a more effective long-term strategy for mitigating urban heat.

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It cools down a bit at first, then dries quickly and heats up again. As a result, we only increase the humidity of the air, and the surface temperature returns to its previous level very quickly.