Daily rainfall and temperature data were gathered from the Met Office Integrated Data Archive System ( MIDAS ) , which is freely available for on - line access to UK academics . These data were collected through a network of meteorological stations spread all over the Thames catchment ( and the rest of the country ) . Detailed information on the collection methods and quality control is reported on the Centre for Environmental Data Analysis ( CEDA ) website . Most measurements are made with full traceability to national or international standards . The daily precipitation , minimum temperature and maximum temperature data from all the available stations within the Thames catchment were interpolated on a 5 × 5 km grid using the Thiessen polygon method , and then the daily average precipitation and temperature series were computed and used as model input .