Is it good to visit jiuzhaigou during spring end April? How is the sight and temperature? Any rain?

The scenery is just so so in the end of April. You see more green trees and the water is not that plentiful, so more or less lack of charms. The best timing to visit is Sep. to Oct. Or change your plan to June for better views than April.

It may be a little cold there in late April, with the temp ranging from 5C/41F to 15C/59F. Wear sweater, leather jacket and jeans. Showers may happen every now and then, and it stops soon, which won't affect sightseeing a lot.