normal rainfall meaning in English

平均降雨量

The monsoon trough also brought less than normal rainfall to hong kong in may and june . 2004 was the 17th driest year in hong kong since records began in 1884
五、六月份的季风槽为本港带来的雨量亦比正常偏少，这些因素令二四年成为自一八八四年有记录以来第17个最少雨的年份。
O in the century . annual rainfall in hong kong was found to be inversely related to the strength of the monsoon in the preceding winter ( figure 3 ) , e . g . , following the weak monsoon in december 1994 - february 1995 ( preceding winter of 1995 ) , 2754 mm of rainfall were recorded in 1995 , 540 mm more than the normal rainfall of 2214 mm . figure 2
假若冬季季候风偏弱，随后一年雨量偏多的机会亦会较高（见图三），例如1994年12月至1995年2月期间的冬季（即1995年的前期冬季）季候风偏弱， 1995年录得的年雨量达到2754毫米，比气候平均的2214毫米多了540毫米。