When Is Summer 2024 In Usa Dates. 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. This is the longest day of the year and marks the start of summer in the northern hemisphere.

What are the dates for the four seasons in 2024? You can select the calendar for another year or another country in.