Start: When Does Each Season

Seasons are reversed south of the equator. When the Northern Hemisphere tilts toward the Sun, the Southern Hemisphere tilts away. Meteorological Versus Astronomical Seasons | News

We treat the seasons as fixed, immutable pillars of the year, but the reality is far messier—and far more fascinating. The start of a season depends entirely on which clock you are watching: the solar clock, the atmospheric clock, or the ecological clock. when does each season start

Furthermore, because the Earth’s orbit isn’t a perfect circle (it’s an ellipse) and the calendar doesn't perfectly align with the solar year, the dates of these events wobble. They can shift by a day or two depending on leap years and orbital mechanics. Seasons are reversed south of the equator