Heat in Ostrava by neighbourhood
On a hot day the gap between a baking street and a shady neighbourhood full of trees can be bigger than you would expect. Where Ostrava overheats in summer, where it stays cool and what to look for in a flat.
What a heat island is
A city warms up more than the countryside around it in summer: roofs, asphalt and concrete soak up the sun during the day and give the heat back slowly at night. This is called the urban heat island. You feel it most at night, when the hot streets don’t have time to cool down and it is hard to sleep in a flat. Trees, lawns and water do the opposite: they give shade and cool the air by evaporating water.
Which neighbourhoods overheat and which don’t
We compare the surface temperature on summer days from Landsat satellite images, as the difference from the city average, for 24 neighbourhoods. The coolest surface is in Radvanice (-2.6 °C), Heřmanice (-2.4 °C) and Stará Bělá (-2.4 °C). The ones that overheat most are Vítkovice (+6.3 °C), Moravská Ostrava (+5.7 °C) and Dubina (+4.9 °C).
Ostrava’s coolest neighbourhoods in summer
- -2.6 °C against the city average Radvanice Radvanice a Bartovice
- -2.4 °C against the city average Heřmanice Slezská Ostrava
- -2.4 °C against the city average Stará Bělá Stará Bělá
- -2.0 °C against the city average Polanka nad Odrou Polanka nad Odrou
- -1.9 °C against the city average Svinov Svinov
- -1.8 °C against the city average Nová Bělá Nová Bělá
- -1.4 °C against the city average Krásné Pole Krásné Pole
- -1.2 °C against the city average Slezská Ostrava Slezská Ostrava
- -0.8 °C against the city average Bartovice Radvanice a Bartovice
- -0.6 °C against the city average Michálkovice Michálkovice
This is the temperature of the surface (roofs, streets, lawns) at the moment of the image, not the air temperature. It still shows the differences between neighbourhoods well: where the surface is warmer, the air and above all the nights tend to be warmer too.
Trees cool the most
The largest share of land under tree and shrub canopy is in Radvanice (53 %), Slezská Ostrava (48 %) and Petřkovice (39 %). A tree in front of a building shades the façade and the pavement and can cool a street noticeably in summer, so look at the greenery in the street itself, not just at a park a few blocks away.
Ostrava’s neighbourhoods with the most trees
- 53 % of the area under trees Radvanice Radvanice a Bartovice
- 48 % of the area under trees Slezská Ostrava Slezská Ostrava
- 39 % of the area under trees Petřkovice Petřkovice
- 35 % of the area under trees Michálkovice Michálkovice
- 32 % of the area under trees Bartovice Radvanice a Bartovice
- 31 % of the area under trees Stará Bělá Stará Bělá
- 30 % of the area under trees Heřmanice Slezská Ostrava
- 29 % of the area under trees Hrušov Slezská Ostrava
- 27 % of the area under trees Svinov Svinov
- 24 % of the area under trees Zábřeh Ostrava-Jih
What to look for in a flat
- Floor: a flat under a flat roof without insulation gets the hottest in summer. Attic and top-floor flats need a well-insulated roof.
- Windows: south- and especially west-facing windows catch the afternoon sun. Ask whether external blinds or shutters can be fitted: shading outside works much better than inside.
- Ventilation: a flat with windows on two sides of the building can be aired by a through draught at night. The courtyard side tends to be quieter and often cooler.
- Surroundings: trees in the street, a park or water nearby do more than the neighbours’ air conditioning. A hot car park or a large area of roofs under the windows gives the heat back at night.
- An older brick building with thick walls stays cool longer than a light structure; in new builds, ask about shading and heat-recovery ventilation.
Frequently asked questions
Where is it coolest in Ostrava in summer?
According to satellite images, the coolest summer surface is in Radvanice (-2.6 °C against the city average), Heřmanice (-2.4 °C) and Stará Bělá (-2.4 °C). Trees, woods and water do most of the cooling.
Which part of Ostrava overheats the most in summer?
The warmest surface is in Vítkovice (+6.3 °C against the city average), Moravská Ostrava (+5.7 °C) and Dubina (+4.9 °C). What overheats are mainly roofs, asphalt and concrete without shade.
Where are the most trees in Ostrava?
The largest share of land under tree and shrub canopy is in Radvanice (53 %), Slezská Ostrava (48 %) and Petřkovice (39 %), based on the satellite land cover map.
