Seasonal fluctuations of the physicochemical conditions were recorded from five temporary ponds in the New Forest, over a period of two years. Diurnal fluctuations were also recorded. Physicochemical factors studied were pond volume; air, water and substratum temperature; water pH; water conductivity; and water dissolved oxygen level. The observed patterns of fluctuation are discussed and a concept of pond stability, to which the fluctuations may be related, is advanced.