The "start" of winter weather varies enormously across the USA due to its size and diverse climates.
This is the traditional calendar definition most people learn in school. It is based on the Earth's tilt and its orbit around the sun. when start winter in usa
Intense winter storm activity is likely across the Midwest, Great Lakes, and Northeast, often accompanied by strong lake-effect snow. the weather often arrives much sooner.
"Winter" means different things in different parts of the USA. While the calendar says late December, the weather often arrives much sooner.