In 2017, the average duration of sunshine in Hengyang is about 1484.2 hours, which is 47.5 hours less than that in the previous years and 28.6 hours less than that in 2009. Compared with the precipitation and temperature, monthly duration of sunshine is relatively stable. Changes in 81.7% months are within normal range, and months in which the duration of sunshine anomalies less than 50% accounted for 8.3% and more than 50% above normal accounted for 10.3%. In this year, March is the period that the duration of sunshine is much significantly higher than other months--75.0% above normal over the past several years, among which the urban area and Qidong County are extremely abnormal ones, because the urban area bias up to 116.7%. In June, the duration of sunshine is 60.2% lower than  normal and climate evaluation describes this to be  significantly less than normal.