During winter, the valleys (Dehradun, Rishikesh, Haridwar) experience rapid nocturnal cooling. Cold, dense air gets trapped below warmer air above. This inversion layer acts like a lid, preventing vertical mixing. The boundary between cold valley air (below) and warmer mountain air (above) becomes a sharp horizontal interface.

The Mussoorie Winterline is a rare atmospheric phenomenon appearing as a glowing, multicolored horizon of red, yellow, and mauve at sunset between late October and February. Visible only in Mussoorie and parts of Switzerland, this "false horizon" is best observed from high-altitude spots like Lal Tibba, Landour, and George Everest House. For more details, visit Times of India . Reddit +2 AI can make mistakes, so double-check responses Copy Creating a public link... You can now share this thread with others Good response Bad response 3 sites The magical Winterline by night, and by day. The ... - Reddit Dec 9, 2016 —