What is the last day of summer?

The "last day of summer" isn't a universally defined date. It depends on whether you're considering:

• The Meteorological Summer: This runs from June 1st to August 31st in the Northern Hemisphere. Therefore, the last day of meteorological summer is August 31st. This definition is preferred by meteorologists as it aligns with seasonal temperature patterns.

• The Astronomical Summer: This is determined by the Earth's tilt and its position relative to the sun. It begins on the summer solstice (around June 20th or 21st) and ends on the autumnal equinox (around September 22nd or 23rd). Therefore, the last day of astronomical summer varies slightly each year, falling on either September 22nd or 23rd. This is the date when day and night are roughly equal in length.

So, depending on your definition, the "last day of summer" is either August 31st or September 22nd/23rd. Many people associate the feeling of summer's end with the time around the autumnal equinox, even though it's technically not the last day according to the meteorological calendar.