Water temperature in Czechia

Czech rivers through the summer

The Czech Republic has no coastline, so people swim in rivers, reservoirs and the many fishponds of South Bohemia. The major rivers, among them the Vltava, Labe and Morava, along with the Sázava, Berounka, Jizera and Lužnice, warm up considerably in high summer, especially on slow-flowing stretches. Below large dams, however, the water often stays cool all summer because it is released from deep in the reservoir. Rivers tend to peak in July and August and cool noticeably in September.

All 251 sites come from the Czech Hydrometeorological Institute, ČHMÚ, which measures water temperature continuously at its river gauges. These are river stations only. Reservoirs, ponds and bathing lakes are not yet part of this dataset, so the readings mainly show how warm a river is at a given gauge. They offer useful guidance for nearby swimming spots, though conditions on the ground can differ.

Regional public health stations test water quality at bathing sites during the season and publish the results. In warm weeks, cyanobacteria can multiply in ponds and reservoirs, and swimming is then discouraged. In rivers, weirs and current are the main hazards, including on popular canoeing routes. Water levels can rise quickly after rain, and releases from dams can increase the flow at short notice.