Firstly, the climate will depend on the places you plan to visit, also the month of October marks the beginning of Winter in India and hence you’re more likely to face the cool weather.
The cold winds of October won’t let you to wear summer clothing, specially in the evening when the sun sets, so before coming, be prepared with some of the woolen stuff. Sweaters, Sweat shirts, light jackets, cotton wear, shawls are some of the belongings that will provide warmth during this month. Light winter clothes will work during October.
It is advised that Visitors must carry strong pair of shoes for walking and touring hills as Himachal Pradesh mostly consist of hilly regions.