This describes the main features of the climate of Southern England from Kent westwards to Wiltshire and Dorset. Much of the eastern half of this area is densely populated, as it includes Greater London and centres of population such as Reading, Slough, Southampton, Portsmouth, Brighton and the Medway towns. There are large areas of open countryside in the area as well, including the North and South Downs, the Chiltern Hills, Salisbury Plain and the Dorset Downs. Most of the area is below 100 metres above sea level but the hill and downland landscapes include large areas over 100m and high points such as Butser Hill, Hampshire (270 metres), Leith Hill, Surrey (294 metres) and Walbury Hill, Berkshire (297 metres). The eastward flowing Thames and its tributaries drain the northern half of the area, whilst elsewhere rivers such as the Arun, Test, Itchen and Avon flow southwards to the English Channel. In Kent, the Medway and its tributaries flow north to the Thames estuary.
Southern England is the part of the UK closest to continental Europe and as such can be subject to continental weather influences that bring cold spells in winter and hot, humid weather in summer. It is also furthest from the paths of most Atlantic depressions, with their associated cloud, wind and rain, so the climate is relatively quiescent.