The peak season for Bir Billing is during the months of April to July. Although Bir BIlling is visited round the year by travellers because of the increased adventure activities. So you can plan your trip anytime of the year except for monsoon. I am attaching with this message some posts that will help you plan your trip
Hi Mehul, October to June is the season for paragliding. Even October – November and March – June are the best time for long flights. Paragliding experience during December, January is different as all the mountains around covered with snow, even Billing experience snowfall during that period.