The authors describe the development of a 0.5° latitude/longitude gridded dataset of monthly terrestrial surface climate from 1901 to 1996. The dataset includes seven climate elements: precipitation, mean temperature, diurnal temperature range, wet-day frequency, vapour pressure, cloud cover, and ground-frost frequency. The spatial coverage extends over all land areas, excluding Antarctica. Monthly climate anomalies relative to the 1961-1990 mean were interpolated from surface climate data, and then added to a 1961-1990 mean monthly climatology to create grids of monthly climate. Primary variables (precipitation, mean temperature, and diurnal temperature range) were directly interpolated from station observations, while secondary variables (wet-day frequency, vapour pressure, cloud cover, and ground-frost frequency) were derived from merged datasets using empirical relationships with primary variables. The dataset is argued to be an advance over other products due to its higher spatial resolution, longer temporal coverage, broader suite of surface climate variables, and strict temporal fidelity. The dataset is available from the Climatic Research Unit.The authors describe the development of a 0.5° latitude/longitude gridded dataset of monthly terrestrial surface climate from 1901 to 1996. The dataset includes seven climate elements: precipitation, mean temperature, diurnal temperature range, wet-day frequency, vapour pressure, cloud cover, and ground-frost frequency. The spatial coverage extends over all land areas, excluding Antarctica. Monthly climate anomalies relative to the 1961-1990 mean were interpolated from surface climate data, and then added to a 1961-1990 mean monthly climatology to create grids of monthly climate. Primary variables (precipitation, mean temperature, and diurnal temperature range) were directly interpolated from station observations, while secondary variables (wet-day frequency, vapour pressure, cloud cover, and ground-frost frequency) were derived from merged datasets using empirical relationships with primary variables. The dataset is argued to be an advance over other products due to its higher spatial resolution, longer temporal coverage, broader suite of surface climate variables, and strict temporal fidelity. The dataset is available from the Climatic Research Unit.