The winter arc phrase came from Gen Z culture on TikTok and is a spin on the idea of a “character arc” or journey a character goes through during a season of a TV show or movie. Being “in your winter arc” simply means you’re on a journey of self-improvement over the colder months of the year. The Winter Arc Challenge is a 90-day self-improvement, personal development trend focused on health habits and goal setting. Learn the winter arc challenge rules. Discover what the Winter Arc is, its meaning, rules, and contract to take advantage of this winter trend to improve your well-being. Complete guide. The “winter arc” refers to the “90 days before the end of the year where you can get ahead of the ‘New Year, new me’ crowd and hit your goals,” TikToker @jessback2earth explains.