Abstract
The occurrence of snow‐lying at the morning observation hour has been reported at a number of stations in the British Isles since 1912 and at a larger number since 1914. By 1940 the number of stations recording this element had increased to approximately 300 in Great Britain alone. Thus the net‐work of stations is now fairly close. The majority of the observing stations are on moderately low ground, that is below 500 ft. above m.s.l. Variations in the duration of snow‐cover in the British Isles are great from year to year and in many of the winter months of the present century the number of days of snow‐lying on low ground has been few. The three consecutive winters of 1940, 1941, and 1942 were, however, unusually severe; the snowfall was considerable and the number of days of snow‐lying comparatively large. In this paper maps showing the distribution of the number of days of snow‐lying for each of the six months January and February, 1940, 1941 and 1942 are given and the different distributions are discussed in relation to the mean temperature, the amount and frequency of snow‐fall and the period of the month at which the snow occurred. In conclusion the entire absence of days with snow‐lying at the majority of stations, in February, 1943, is noted.