Friday, June 20, 2025, marks the first astronomical day of summer in the Northern Hemisphere. It is also known as the summer solstice or June solstice and the longest day of the year., When is the first day of summer? Date and time of the southern and northern hemisphere summer solstice 2025, which marks the start of summer season., When Is The First Day Of Summer 2025? The first day of summer arrives with the solstice this year on Friday, June 20, 2025, 10:42 p.m. EDT. For those of us in the Northern Hemisphere, the Earth tilts mostly toward the Sun during this time., Is the summer solstice the first day of summer? Yes, astronomers recognize the summer solstice as the official first day of summer in the northern hemisphere, according to NASA. The National Centers for Environmental Information explains that solstices and equinoxes mark the start of the astronomical seasons. These events occur when the sun , The summer solstice falls late in the day on Friday, June 20 in the United States. It's also the first official day of summer. Do you yearn for long days and short nights?, Summer officially begins in the Northern Hemisphere on June 20 with the summer solstice, the day with the greatest amount of possible daylight and the shortest night. For ease of recordkeeping, meteorologists and climatologists consider June 1 the first day of summer, but astronomically speaking .