It's still cold. There are winds, even sand storms. Also, the weather changes a lot, sometimes hot at noon and sometimes cold.
So bring long-sleeve t-shirt, sweater and a warm coat and be ready to get changed anytime according to the weather. You may pay attention to Beijing Weather(https://www.travelchinaguide.com/climate/beijing.htm) before going. The weather report is on the left side of the page.