Summer 2024. Summer 2024 the hottest ever, eu climate change monitor says. Summer 2024 starts on thursday, june 20th in the northern hemisphere, with the first day of summer being the longest daylight day of the year with the earth's axis having reached its furthest tilt and begins to change.

Therefore, the summer solstice is not considered to be the first day of summer, meteorologically speaking. In this system, summer begins on june 1 and ends on august 31.