Morbidity and mortality rates from cardiovascular diseases have been shown to undergo seasonal variations and it has been suggested that these variations may be attributed to weather changes. Epidemiological studies have shown a peak of coronary and cerebral vascular morbidity and mortality during the cold season. Large increases in morbidity and mortality from cardiovascular diseases during the hot summer weather and heat waves have also been shown. It has been observed that, among the meteorological factors, temperature has the highest effect on the incidence of cardiovascular diseases. Cold and heat appear to have an acute effect on the incidence of cardiovascular diseases, while the possible chronic effect has rarely been investigated.