September to November will be the proper time to visit Manali..
But recently make a plan to visit Manali on Late December and early January to enjoy the chilling weather at those time..
It really depends on what are you looking for. I have been to Manali 5 times now and each time I fell in love with the town. I visited in December once and got heavy snowfall. It was amazing. I visited in September once and the weather was quite pleasant mostly, but it was raining a lot. I visited in March and April twice and I think that is the best of Manali I have ever seen.
Hello, Manali is a perfect place for a quick weekend getaway. You can reach there by road (car/bus) or simply take a flight till Bhuntar and then hire a cab till Manali. Since Winter season is coming close, I will suggest you to visit Manali from mid-December to February if you want to enjoy snow. Manali can be visited anytime of the year. Just avoid going during peak months such as May-July and long weekends/holidays.
October to February is the winter season and is considered to be the best time to visit Manali if you like the cold and January is best to enjoy the chilly pleasure of fresh snowfall . The temperature drops down below zero degrees Celsius. Summer in the region starts in the month of March and lasts till June.