Mean annual number of summer days (daily 2 m maximum temperature equal or above 25°C) for Linz and surrounding area between 1971 and 2000 using urban climate simulations carried out with the model MUKLIMO_3 (Sievers, 2016) and applying a dynamical-statistical downscaling approach, called the "cuboid method" (Früh et al., 2010) that takes into accoung long-term meteorological data from the monitoring station Linz Hoersching. References: Sievers U. (2016). Das kleinskalige Strömungsmodell MUKLIMO_3 Teil 2: Thermodynamische Erweiterungen. Berichte des Deutschen Wetterdienstes Band 248, 151 S., ISBN 978-3-88148-490-9; Früh et al. (2010). Estimation of Climate-Change Impacts on the Urban Heat Load Using an Urban Climate Model and Regional Climate Projections. Journal of Applied Meteorology and Climatology, 50(1), 167-184 The dataset has been created within the CLARITY project (http://clarity-h2020.eu/), funded by the EU Horizon 2020 programme.