1st Day Of Summer 2024 Usa Calendar. The season change dates are based on the spring and fall equinoxes as well as the summer and winter solstices. That also happens to be the summer solstice, aka the start of summer.

This year’s summer solstice will arrive this thursday on june 20 for the northern hemisphere, according to nasa. The first official day of summer astronomically for 2024 is thursday, june 20, which is when the northern hemisphere has the longest day of the year, according to the.