Modelling daily weather with multivariate time series

Existing methods of modelling daily weather commonly put undue emphasis on modelling rainfall, and model non-rain variables separately for wet and dry days. This work adopts an alternative approach of modelling the non-rain variables simultaneously, then modelling rainfall as a function of the non-rain variables. Five non-rain variables are included, across four sites in Scotland. The overall model has been developed in such a way as to allow the effects of changes in climate to be incorporated in a flexible manner. Good agreement is demonstrated between a 20-year run of daily weather at one site and two 20-year simulation runs.