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SUMMARY An analysis was made of recent observations of solar radiation receipt in upland areas and the longer term data of hours of bright sunshine. Estimates were made of the means and spatial variabilities of these quantities in upland regions of the U.K. It is concluded that: (1) There is a decrease in solar radiation receipt, with increasing altitude, of 2-5-3 MJ m-2 day - km -. This is due to increased cloud cover and is probably more dependent on regional mean altitude than on the altitude of the station. (2) The altitudinal gradient of sunshine duration is 1-3 hour day - km-'. Given the uncertainties in the relationship between sunshine and solar radiation, this value is consistent with the observed gradient of solar radiation. (3) In cloudless conditions, solar radiation increases by approximately 15%. per 1000 m; this is the value which would be expected theoretically from the scattering of solar radiation by aerosol and water vapour. (4) Above 1000 m, the land is frequently above the level of the cloud tops, at least in the summer, so that solar radiation receipt is as much as 35 % greater on the summit of Cairngorm.