Abstract
Actual number of the freeze-thaw days in one year is counted for about 2, 000 stations in Japan and their distribution maps are made for each months and the whole year of 1955. Fig. 1 and Fig. 2 show the examples of January and March respectively. In January the maximum number is found on the Kantô Plain, while the minima are at the centre of Hokkaidô and in southern Kyûshû. Distribution of the freeze-thaw days for the whole year is shown in Fig. 3. The maximum is found not at the top of mountains but on the plateau of eastern Hokkaidô.
