anticyclone

Anticyclones are formed when areas of descending air result in high pressure. They bring more stable conditions and can stay in place for days or even months. Summer anticyclones bring hot sunny days. Winter anticyclones bring cooler weather with a possibility of fog and freezing conditions.

Area of high atmospheric pressure caused by descending air, which becomes warm and dry. Winds radiate from a calm centre, taking a clockwise direction in the northern hemisphere and an anticlockwise direction in the southern hemisphere. Anticyclones are characterized by clear weather and the absence of rain and violent winds. In summer they bring hot, sunny days and in winter they bring fine, frosty spells, although fog and low cloud are not uncommon in the UK. Blocking anticyclones, which prevent the normal air circulation of an area, can cause summer droughts and severe winters.