What Is The Official First Day Of Summer 2024. In the southern hemisphere, it will occur on december 21, 2024. And how do the words summer solstice tie in?

Fall starts at the moment when the sun is directly over the equator, going from north to. Thursday, june 20 is the official first day of northern astronomical summer for 2024 — summer solstice — which is the longest day of the year for this half of the planet.