What Is The First Day Of Summer 2024 Solstice. In the southern hemisphere, it will occur on december 21, 2024. No world body has designated an official day to start each new season, and different schools of thought or traditions define the seasons in.

Today (june 20) the summer solstice — the longest day of the year in the northern hemisphere — will begin, and it will be the earliest solstice in 228 years.  — this year, new zealanders rang in autumn on march 20 and winter on june 21, and soon we’ll celebrate spring on september 23 and summer on december 21.