Adapting climate model data to urban drainage applications can be done in several ways but a popular way is the so-called ‘delta change' method. In this method, relative changes in rainfall characteristics estimated from climate model output are transferred to an observed rainfall time series, generally by multiplicative factors. In this paper, a version of the method is proposed in which these ‘delta factors' are related to the rainfall intensity level. This is achieved by calculating changes in the probability distribution of rainfall intensities and modelling the delta factors as a function of percentile. The model is applied to 30-min output from the RCA3 regional atmospheric climate model, in a grid box covering Kalmar City, Sweden. The climate model results indicate an increase of the highest intensities by up to ~20% and a decrease of lower intensities by up to almost 40%. This result is valid for a 30-min time scale, and to evaluate whether urban drainage impact assessment can be meaningfully performed on this time scale, a MOUSE model was applied in Kalmar using different time steps. The results indicate that a 30-min time step may be meaningful, but that ways to transfer the rainfall changes also to data of a higher time resolution needs to be considered. This will be done in future studies, as well as further testing and evaluation for other Swedish cities.