This dataset contains a set of reference long term averages for observed climate variables on an approximately 25km resolution grid. This matches the resolution of the HadRM3 regional climate model and the UKCP09 climate projections. These data represent the baseline reference climate averages for the period 1961 – 1990.

The data were derived from the Met Office gridded land surface climate observations – long term averages at 5km resolution (see related dataset). Each 25 x 25km grid box value is an average of the 5 x 5 km grid cell values that fall within it. Averages have been calculated for each month, season and the year as a whole (17 data sets). For the days of frost and days of rain variables the seasonal and annual averages are the total of the individual monthly averages. For the remaining variables the seasonal and annual averages are the mean of the monthly averages (allowing for differences in month length). To facilitate combining the baseline data with the UKCP09 climate projections, the 25 km baseline averages for rainfall have been expressed in units of millimetres per day (rather than total millimetres, as for the 5 km data sets).

The data are provide in CF-1.5 compliant NetCDF format. The data are additionally provided in ESRI-ascii format, suitable for ingestion in GIS applications, and a simple timeseries format for users requiring a limited number of points.