Today is the first day of summer! Yes, you probably got out of school weeks ago, but that wasn’t the real first day of summer. Today is the summer solstice, marking the actual, scientific start of the summer season.
What is the summer solstice? Solstice is derived from the Latin words sol (sun) and sistere (to stand still). More importantly, summer solstice is the first day of summer and the longest day of the year. But there’s more to it.
Earth orbits around the sun on a tilted axis — it’s not sitting straight up. Between March and September, Earth’s Northern Hemisphere is leaning more toward the Sun, getting more exposure to direct sunlight over the course of any single day. (As you can imagine, winter solstice is just the opposite. Look for that special day on Dec. 21.)