Abstract: First, it is discussed that the anomaly in long-range weather is due to sustained stable circulation. Waves in monthly or seasonal departure maps can be regarded essentially as probability waves which reflect the anomaly distribution of cold and heat sources on earth surface. The persistent stable circulation creates these distributions which serve as persistent disturbance sources and in turn feedback the general circulation with persistent stability in later period. The departure probability waves in six-month (Sept,-Feb.) charts reflect the abnormal distribution of cold and heat sources on earth's surface which move slowly in north of 30°N and eastward on Eurasian continent in opposition to temperature gradient. But the waves are stationary in south of 30°N. The characteristics of the six-month departure probability waves are used to develop a statistical model to predicate spring-summer temperature and precipitation of next year. It has been tested in several North China provinces for four years with encouraging results.