There are some factors/criterions that makes some period peak season and lean season.
1-Vacation Rush,
2-Cool season when Rains have stoopped, and also Winter not started.
3-Marriage ceremonies rush.
4-Corporate LTC period where many executives...
more... prefer to take family with them on holidays and this is normally in summer vacations or Diwali/Christmas vacations as per their convinience.
5-Foreign tourist prefer winter to travel India seeing the hotness preaviling most of the time in most part comparted to Europe, America North East Asia.