Zhangjiajie is very cold in winter, some scenic spots are closed for the roads are slippery and not safe to walk on them, such as Tianmen Cave, The Glass Road, Zhangjiajie Grand Canyon.  So is AVATAR Mountain available in winter? can I have the chance to enjoy the Hallelujah Mountain in Zhangjiajie National Forest Park? Yes, you can still visit AVATAR Mountain even in winter. Generally speaking, there are 3 ways up Yuanjiajie in Zhangjiajie National Forest Park:
Bailong Elevator: Take Bailong Elevator up Yuanjiajie is the easiest and fastest way, Bailong Elevator is the said to be the world's tallest full-exposure outdoor lift, tallest double-deck sightseeing elevator, it only take you less than 3 minutes up mountain. The elevator runs throughout whole year, even it snows in the park. The ticket of Bailong Elevator is 72RMB/PAX.
Yangjiajie Cablecar: First, you need to take shuttle bus to get to the entrance of Zhangjiajie National Forest Park, then take tourist bus to Yangjiajie cablecar station. Yangjiajie Cablecar is a new cablecar in Zhangjiajie National Forest Park, it was completed in March and open to public in 2015, after arriving the top of Yangjiajie Mountain, there are a lot of tourist buses runing between Yangjiajie and Yuanjiajie, about 20 minutes riding and it is free.
Hiking up from Golden Whip Stream: Following a heavenly valley for several kilometers, the path then branches off and returns to the entrance beneath the Yearning Couple, there is a trail you can hike up the Bewitching Terrace, more than 5000 steps you need to climb up and it may be slippery in winter time, this route is only good for the hiking lovers.