What do you consider the start of summer?

May 19th, 2009 at 4:22 pm by under Uncategorized, Weather

Many Americans view Memorial Day as the unofficial beginning of summer and Labor Day as the unofficial end of the season. “Unofficially” speaking this summer will be the longest possible.

Memorial Day, which is on the last Monday in May, is on its earliest day possible this year, May 25th. Meanwhile, Labor Day, the first Monday in September, is on its latest day possible, September 7th.  The key word here is unofficial.

Meteorologically speaking, summer occupies the months of June, July and August in the northern Hemisphere… but it still isn’t the official start of summer. One look at the 2009 calendar reveals that summer officially starts on June 21st. It marks the summer solstice and the astronomical and official start to summer.

To understand the way the seasons work, let’s back track to the first of spring. On the vernal equinox the northern and southern Hemisphere’s receive an equal amount of light, and days occupy nearly the same amount of time as the nights.
vernal-equinox

But on the day following the vernal equinox, the northern Hemisphere will begin to tilt towards the sun. By the time the summer solstice arrives (June 21), the earth tilts as far towards the sun as possible. This marks the longest day of the year. In Green Bay the sun will rise at 5:07 AM and set at 8:40 PM, which converts to over 15 hours of daylight.
summer-solsticeBut on the very next day, the northern Hemisphere will begin to tilt away from the sun, and we will slowly head towards another long Wisconsin winter… sorry I had to bring it up.

So as you fire up your grill this weekend, and soak in all of the activities that Memorial Day weekend offers, remember that while it will feel like summer, the official start to the season is still a few weeks away.

Until Next Time,

Meteorologist Andrew Thut

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