ReFH 2 allows you to choose to model either a winter or a summer event under the “Model Parameters” tab in the final modelling screen. The software defaults to a winter event.
It is recommended that a winter event is used in all bar the heavily urbanised catchments with URBEXT2000 values greater than 0.3. This is described in more detail in Section 8 of the ReFH 2 Technical Report.
There is ongoing research into small urbanised catchments therefore this guidance may be updated to reflect the outcomes of this research if the recommendations change.