Hi Gowtham, Nainital maintains fairly pleasant weather the majority of the year and is a year-round. destination. However, October brings with it a chill in the air, especially at night. Days are neither hot nor too cold. You would require a blanket at night and maybe a light sweater during the day. October is an ideal time to go for those who don't wish to experience the freezing cold that November brings with it. November marks the onset of winter and it continues till the end of January. Hope this helped. Have a good trip!