Qingming, is also called Tomb-sweeping Day, is a time for Chinese people to honor ancestors, remembering the dead and pay respect to the family members departed. It falls on April 5 of every year. (It’s approved to be a holiday from April 3 to 5 by Chinese government.)
A well-known poem written by Du Mu, a poet of Tang Dynasty tells of a sad scene in early April: "rains fall heavily as Qingming comes, and passers-by with lowered spirits go."