The relation of air temperature between early summer and early autumn from 1916 to 1966 was investigated. The data are brought by the statistical analysis for the purpose of the long range weather forecast. he results are summarized as follows : 1. The air temperature in early autumn at Mokpo is largely influenced by that of early summer. That is, when the air temperature in early summer is higher than the average, the temperature in early autumn has the possibility of being higher temperature in early autumn than average, the possibility being as much as $60\%$. On the contrary, when the former is lower, the latter has a possibility of becoming $74\%$ below the normal year. 2. The monthly ranges of forcastable mean air temperature in early autumn will be computed by the types of total variation in early summer and the standard deviation in early autumn.