【摘要】 从月尺度降水长期预报业务的需要出发，根据中央气象台长期科１６０站月降水资料，分析了中国５月份降水的基本气候特点和长期变化；进一步明确了５月份降水预报业务的工作重点；揭示出某些对５月份降水预报业务有价值的气候现象；其中５月份南北方降水长期变化的阶段性及其反位相振荡现象（ＳＮ现象）对５月份降水长期预报业务具有重要的实践意义。更多还原

【Abstract】 he rainfall principal climate features and the long range rainfall changes of May in China are analyzed,according to the monthly rainfall data of 160 stations in China.Thus rainfall forecasting operational focal prints of May are defined further some useful climate phenomena are revealled for rainfall forecasting operation in May.The rainfall stage features of South China-North China region and their opposite phase(SN phenomena) are of realistic significance for long range rainfall forecasting operation in May.更多还原