Tuesday, June 21, marks this year’s summer solstice, or the first official day of summer in the Northern Hemisphere. Here’s everything you need to know about the summer solstice and its importance.

What happens during the summer solstice?

According to Britannica, the summer solstice is the day “the sun travels travels the longest path through the sky,” resulting in the most daylight and making it the longest day of the year. The North Pole is tilted about 23.4° (23°27´) toward the sun during the summer solstice, while the South Pole tilts the same amount six months later during the Northern Hemisphere’s winter solstice.

When do solstices occur?

Solstices happen every June and December, occurring at the same time around the world and marking the year’s longest and shortest days. The summer solstice typically falls on either June 20 or 21, with the winter solstice following six months later around Dec. 21 or 22, per NASA.

What does ‘solstice’ mean? What is its significance?

According to Fox 9, the word “solstice” has Latin roots, coming from the Latin word “solstitium” — “sol” (sun) and “stitium” (still or stopped). Cultures from around the world celebrate various traditions during the summer and winter solstices, honoring the celestial events with physical structures, festivals and more. For example, Stonehenge and the Great Pyramids at Giza happen to precisely line up with the rising sun on the summer solstice each year, per National Geographic.

Is the summer solstice the hottest day of the year?

While you may believe more sunlight equals more heat, that’s not necessarily the case. According to Spectrum Local News, there is a lag time for oceans and land to heat. The Northern Hemisphere may receive the most hours of sunlight on the summer solstice, but the hottest temperatures won’t come until “around late July or early August, depending on latitude and other factors.”