Hello, The best time to visit Manali to experience snow is from mid-December to January. You can enjoy snow activities with the onset of January (first-half). However, snow roadblocks is a matter of chance and completely unpredictable, but snow roadblocks in Manali usually happen in January. Due to the same, tourists are suggested to walk past the areas. Avoid going to Manali in the mid and later days of January. Also, keep a current track of weather conditions while planning, before and throughout the transfers during the tour. Help from a native resident is preferrable for better and clearer information.
Have a safe journey!