According to the latest weather forecast of Huashan, it will be cloudy on April 3rd there, and the temperature will be 5-15C. I think you have to wear a sweater and a thick jackets at day time. Tourists there usually climb the mountain from mid-night to see the sunrise on the peak, so you'd better take a down coat as well. There are also long cotton overcoat for rent at the entrance of the mountain if you don't want to take too much clothing.

you can have the weather information in the huashan official website www.huashan16.com,