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无锡市是柑桔栽培的北缘地区,位于北纬31°25′,东经120°8′。年平均气温15.3℃(1954～1985年的平均温度,下同),年降雨量1057毫米,冬季绝对最低气温-12.5℃(1969年2月6日),全年无霜期240天。自1964年开始种桔至今的23年间,气温在-9℃以下的年份有4次,在-8℃以下的年份有5次,柑桔多次受冻。尤其1969年和1977年最低温度达-12.5℃和-11.8℃。其中1977年低温持续时间长,积雪冰冻时间较久,为50余年来所未见,桔树枝干冻裂,枝叶枯黄,受冻惨重。
Wuxi City is the northern margin of citrus cultivation, located at latitude 31 ° 25 ’and longitude 120 ° 8’. The annual average temperature of 15.3 ℃ (1954 ~ 1985 average temperature, the same below), the annual rainfall of 1057 mm, the absolute minimum temperature in winter - 12. 5 ℃ (February 6, 1969), the annual frost-free period of 240 days. In the 23 years since the beginning of the cultivation of orange in 1964, there have been 4 times in the year below -9 ° C and 5 times in the year below -8 ° C. In particular, the lowest temperatures in 1969 and 1977 reached -12.5 ° C and -11.8 ° C. Including 1977, a long duration of low temperature, snow frozen for a long time, for more than 50 years have not seen, orange branches freeze-dried branches and leaves yellow, suffered heavy snowfall.