The Weather Notebook: A Long Summer

A Long Summer
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Dave Thurlow, Host

If this sultry, steamy summer felt like it dragged on longer than three months, you're right. The summer did go on for more than three months. But, in fact, every summer pulls the same trick. Hi, I'm Dave Thurlow from the Mount Washington Observatory and this is The Weather Notebook.

A hot day on the beach at Bird Island, 1924 - NOAA Photo
In the Northern Hemisphere, summer is always the longest season of the year. It lasts about 93 and 1/2 days. Winter, believe it or not, only lasts 89 days. People have known this since the days of Stonehenge, but had a hard time reconciling this observation with the belief that the earth was the center of a circular universe.

In the 1500s, Nicolaus Copernicus put forth the idea that all the planets, including Earth, actually revolved around the sun. This caused quite a theological stir, but this bit of knowledge still didn't solve the puzzle of the unequal seasons. Scientist Johannes Kepler finally figured it out.

Kepler claimed that the earth's orbit around the sun isn't a perfect circle. Instead, it's ever so slightly egg-shaped, with the sun a bit off center. Kepler also found that the earth swings faster through its orbit when it's closer to the sun. The closest approach happens--ironically--in January. This extra closeness isn't enough to keep our cold away. But it does help winter to pass a bit more quickly than summer in the Northern Hemisphere. That's good to know when you're shivering in the dark and waiting for that first crocus to swing into action.

Today's contributing writer is Bob Henson, who also contributes to The Weather Notebook's new companion book called Soul of the Sky. For more information, visit our website at mountwashington.org.