First Day Of Summer 2024 Time Frame. On that day, the autumnal equinox will occur, marking the beginning of fall. Because the earth rotates on a tilt, the summer solstice.

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. Summer 2024 starts on thursday, june 20th in the northern.