This past weekend marked the start of summer. The June (aka Summer) Solstice was Saturday, June 20. Specifically, Saturday at 5:44 P.M. EDT marked the official beginning of summer in the Northern Hemisphere, occurring when Earth arrives at the point in its orbit where the North Pole is at its maximum tilt (about 23.5 degrees) toward the sun. For those who live in the Southern Hemisphere, this is the shortest day of the year and marks the arrival of winter.