Is it summer yet? I suppose that depends on your frame of reference. Memorial Day is now in the rearview mirror, so for many among us it is officially summer. But odds are that your calendar notes the first day of summer is this Saturday the 21st. That is the summer solstice, when the northern hemisphere will be tilted furthest toward the sun than at any other time of the year. It will also be the sun’s highest arch at midday for the year. It is all because of the earth’s angle of rotation and orbit, and for people of higher latitudes it is a special time.
This is all due, of course, to the fact that the earth does not rotate perpendicular to the direction of its orbit. The earth’s angle of rotation is 23.5 degrees off perpendicular. As a result, the directness of sunlight (not the distance to the sun!) varies throughout the year, particularly in the high northern and southern latitudes.
I checked my North Dakota Game and Fish Department calendar for sunrise and sunset on the solstice. In Bismarck sunrise on the 21st is 5:49 a.m. CDT and sunset at 8:41 p.m. That is a whopping fourteen hours and fifty two minutes between sunrise and sunset. As most hunters know (or at least those that read the proclamation), the sun rises and sets about one minute earlier for every 12.5 miles east of Bismarck, Conversely, it will rise and set one minute later for every 12.5 miles west of Bismarck.
That is a lot of sunlight, but it is all downhill from here until the winter solstice in December. The winter solstice will occur on December 21 this year, and sunrise will be at 8:25 a.m. while sunset will occur at 4:57 p.m. CDT. That is a measly eight hours and thirty-two minutes between sunrise and sunset. As most of us well know, it is dark when we go to work and when we head back home. That is the price we must pay for all that summer sun.
As you might expect, the equinoxes and solstices were special days for early cultures. Festivities marking them were held in most if not all cultures around the globe. This has led to the construction of monuments such as Stonehenge, Chicken Itza, and Newgrange to document the equinoxes and solstices. In Europe the summer solstice is often referred to as “midsummer.” Midsummer celebrations often involve fireworks, bonfires, and feasting. In an interesting twist to the celebration in Norway it is said that if a young girl puts flowers under her pillow upon going to bed on the summer solstice she will dream about her future husband.
Natural North Dakota is supported by NDSU Central Grasslands Research Extension Center and Minot State University-Bottineau, and by the members of Prairie Public. Thanks to Sunny 101.9 in Bottineau for their recording services.