BETHLEHEM, Pa. — Brad Klein reviews upcoming astronomical highlights with Bethlehem’s "Backyard Astronomy Guy," Marty McGuire.
This week, a discussion of the different start dates for summer.
Relying on the calendar, "meteorological summer" is simply the warm months of June, July and August.
But there is a more precise way to calculate the start of summer, based not on the calendar but on the position of the Earth as it orbits the sun.
"Astronomical summer" began with the summer solstice, this past Friday. That same moment is the start of winter, south of the equator.
“While June 20th, last Friday, was our longest day of the year between sunrise and sunset, it also ends up being the shortest day of the year for the southern hemisphere,” said McGuire.
“So while we're enjoying our sun up here, they're getting less of it down there.”
But, there are other ways to mark the beginning of summer. Many simply rely on Memorial Day weekend.
And for kids, the last day of school suffices.