The dense fog in Varanasi during December may cause disruptions to transportation, including delays in flights, trains, and early morning boat rides. Travellers should be prepared for chilly weather, especially during evenings and mornings, as temperatures can drop significantly. The foggy conditions may also reduce visibility, posing risks for road travel and outdoor activities. Visitors should plan their schedules carefully, allowing extra time for potential delays, and ensure they are dressed appropriately for the cold weather.