Around 2050, the climate scenario RCP4.5 expects 21.7 heat days a year, days of at least 30 °C, at the median address in Graz, against 11.4 in 1981–2010. Liebenau and Puntigam in the south lead with 23.6 and 23.3, and Ries on the eastern hills has the fewest, 18.8.
A heat day is a day on which the temperature reaches at least 30 °C. ClimaMap Steiermark, the climate maps of the province of Styria, gives the number of heat days a year for the past and for the climate scenarios of the coming decades. We read it for every address in Graz and take the median per district and neighbourhood.
45,186 addresses. 17 districts. 210 neighbourhoods with at least 60 addresses.
How many heat days will Graz have around 2050?
For the years 2036–2065, the scenario RCP4.5 expects 21.7 heat days a year at the median address in Graz. In 1981–2010 it was 11.4. In each of the 17 districts, the number of heat days roughly doubles. The Innere Stadt, the city centre, sits at the city median, with 21.7 heat days around 2050.
| District | Heat days a year, 1981–2010 | Heat days a year, 2036–2065 |
|---|---|---|
| Liebenau | 12.4 | 23.6 |
| Puntigam | 12.4 | 23.3 |
| Straßgang | 11.7 | 22.6 |
| Gries | 12.0 | 22.4 |
| Jakomini | 11.9 | 22.2 |
| Sankt Peter | 11.1 | 22.0 |
| Wetzelsdorf | 11.6 | 22.0 |
| Gösting | 11.3 | 21.8 |
| Lend | 11.7 | 21.8 |
| Innere Stadt | 11.9 | 21.7 |
| Eggenberg | 11.2 | 21.3 |
| Sankt Leonhard | 11.2 | 21.2 |
| Geidorf | 11.3 | 21.0 |
| Andritz | 10.5 | 20.8 |
| Waltendorf | 10.0 | 20.1 |
| Mariatrost | 9.4 | 19.2 |
| Ries | 8.8 | 18.8 |
| All of Graz | 11.4 | 21.7 |
Where in Graz does it get hottest?
The south of the city has the most heat days. Liebenau leads with 23.6 heat days around 2050, followed by Puntigam with 23.3 and Straßgang with 22.6. In 1981–2010, Liebenau and Puntigam shared the highest figure, 12.4. The ten hottest neighbourhoods all lie in Liebenau and Puntigam. The Auwaldgasse area and the Eichbachgasse area in Liebenau share the highest figure, a median of 24 heat days a year.
| Neighbourhood | Heat days a year, 1981–2010 | Heat days a year, 2036–2065 |
|---|---|---|
| Auwaldgasse areaLiebenau | 12.8 | 24.0 |
| Eichbachgasse areaLiebenau | 12.8 | 24.0 |
| Krummer Weg areaLiebenau | 12.6 | 23.8 |
| Jägerweg areaLiebenau | 12.4 | 23.6 |
| Liebenauer Hauptstraße / Engelsdorfer Straße areaLiebenau | 12.4 | 23.6 |
| Liebenauer Hauptstraße / Lorenz-Vest-Weg areaLiebenau | 12.4 | 23.6 |
| Rudersdorfer Straße areaPuntigam | 12.6 | 23.6 |
| Triester Straße / Ruthardweg areaPuntigam | 12.6 | 23.6 |
| Liebenauer Hauptstraße / Ziehrerstraße areaLiebenau | 12.4 | 23.4 |
| Gradnerstraße areaPuntigam | 12.3 | 23.3 |
| All of Graz | 11.4 | 21.7 |
Where in Graz does it stay coolest?
Of the districts, Ries on the hills in the east has the fewest heat days, 8.8 in 1981–2010 and 18.8 around 2050, followed by Mariatrost with 19.2 and Waltendorf with 20.1. The coolest single neighbourhood lies in the north-west, the Raachgasse area in Gösting, with 5.5 heat days in 1981–2010 and 13.5 around 2050.
| Neighbourhood | Heat days a year, 1981–2010 | Heat days a year, 2036–2065 |
|---|---|---|
| Raachgasse areaGösting | 5.5 | 13.5 |
| Weizbachweg areaAndritz | 7.0 | 16.2 |
| Hubert-Hoffmann-Ring areaMariatrost | 7.6 | 16.8 |
| Föllinger Straße areaMariatrost | 7.6 | 16.8 |
| Schönbrunngasse areaGeidorf | 8.6 | 17.7 |
| Mariatroster Straße / Josefweg areaMariatrost | 8.6 | 17.7 |
| Ragnitzstraße / Riesstraße areaRies | 8.2 | 17.8 |
| Ragnitztalweg areaWaltendorf | 8.1 | 17.9 |
| Stiftingtalstraße / Rohrbachhöhe areaRies | 8.7 | 18.5 |
| Stiftingtalstraße / Ortnerstraße areaRies | 8.8 | 18.6 |
| All of Graz | 11.4 | 21.7 |
The lists include neighbourhoods with at least 60 addresses.
How we counted
ClimaMap builds on ÖKS15, the climate scenarios for Austria, and gives the heat days on a grid of 1 km squares, so neighbouring addresses share one value. In the scenario RCP4.5, emissions peak before the middle of the century and then fall. The report for each address on the map of Graz also shows the high-emission pathway RCP8.5 and the end of the century. The method page gives the rule for each part. ClimaMap covers Styria, and Graz is the one Lagecheck city in Styria, so this story is about Graz alone.