根据江苏省苏州市东山县1956～1984年和1999～2003年银桂（Osmanthus fragrans）物候资料和同期气象资料，应用数理统计方法分析了银桂初花的气候指标，发现银桂初花期与初花前最低气温和相对湿度关系密切。早银桂初花的气候指标为：日最低气温10 d滑动平均稳定≤23.0 ℃，同时日最低气温<22.0 ℃，满足这指标之后3～12 d早银桂初花；或当日最低气温10 d滑动平均稳定在23.0～25.5 ℃，同时日平均相对湿度≥88%连续在3 d（包括 3 d）以上，在这日期之后的12 d内早银桂初花。晚银桂初花的气候指标为：当日最低气温9 d 滑动平均稳定≤20 ℃，同时日最低气温<19.5 ℃，满足这指标后4～12 d晚银桂初花；或当日最低气温9 d滑动平均稳定在20.0～21.5 ℃，同时日平均相对湿度≥88%连续在3 d（包括3 d ）以上，在这日期之后的6 d内晚银桂初花。日最低气温10 d滑动平均稳定>25.5 ℃时，早银桂不开花；日最低气温9 d滑动平均稳定>21.5 ℃时，晚银桂不开花。晚银桂和早银桂初花期存在显著的相关，相关系数为0.443 8(n=34)，平均初花期晚银桂比早银桂迟15 d。由于受全球气候变暖的影响，1999～2003年苏州东山地区银桂类初花期比1956～1984年推迟了7～8 d。
Climatic indices for initial flowering in Osmanthus fragrans were analyzed statistically by comparing the phenological data and climate data from 1956 to 1984 and from 1999 to 2003 in Dongshan County, Suzhou, Jiangsu Province, China. The results showed that the initial flowering date of O. fragrans was closely relate d to daily minimum temperature and relative humidity. For early flowering O. fragrans, initial flowering occurred 3 to 12 days later following a condition that the daily minimum temperature of 10_day_moving_average (DMTMA10)≤23.0 ℃ and the daily minimum temperature <22.0 ℃, or 12 days later following a condition that DMTMA10 stays between 23.0 and 25.5 ℃ and the daily average relative humidity (DARH)≥88% for 3 or more than 3 days. It would not get flowering if the DMTMA 10>25.5 ℃. For late flowering O. fragrans, initial flowering occurred 4 to 12 days later following a condition that the daily minimum temperature of 9_day_moving_average (DMTMA9)≤20.0 ℃ and the daily minimum temperature <19.5 ℃, or 6 days later following a condition that DMTMA9 stays between 20.0 and 21.5 ℃ and the DARH≥88% for 3 or more than 3 days. It would not get flowering if the DMTMA9>21.5 ℃. The date of initial flowering of early flowering O. fragrans and that of late flowering O. fragrans were significantly correlated (r=0.443 8, n= 34). The initial flowering date of late flowering O. fragrans is, on average, 15 days later than that of the early flowering O. fragrans. The initial flowering date of both types ofO. fragrans during 1999 and 2003 was postponed 7－8 days compared with that during 1956 and 1984 in Dongshan County due to global climate warming.