When Does Winter Start? _top_ May 2026

The seemingly simple question has two different correct answers, depending on whether you are following definitions (based on Earth’s tilt and orbit around the sun) or meteorological definitions (based on the annual temperature cycle and calendar for record-keeping).

Here is the detailed explanation of both. This is the most commonly cited answer in calendars, folklore, and popular culture. It is defined by Earth’s 23.5-degree axial tilt and its position relative to the sun. when does winter start?