The smoke days and the frost-freeperiod increase, while sunshine hours decreased.
烟霾日数、无霜期呈增加趋势，而日照时数为减少趋势。
2
Change at the annual frost-freeperiod 100-160 days, the distribution of the trend of growing on the grounds east to west.
全年无霜期变化在100—160天之间，分布趋势为由东向西逐渐增长。
3
Chenghai is located in the subtropical zone, a subtropical monsoon climate, warm and pleasant, very hot short, a long frost-freeperiod, the Four Seasons is not clear.