Well, I certainly hope that everyone had a wonderful time with family and friends on Christmas. And do you know what? Santa’s in the midst of giving us one more present, INCREASING DAYLIGHT. By the end of this month, this Sunday, we will be receiving 5 more minutes of daylight than we did on the 21st. And by the end of January, the daylight gain since Dec. 21 will be up to 1 hour and 5 minutes. So hang in there, as the darkest days will soon be receding.
Meanwhile, what will continue to decrease for several more days is the Earth-Sun distance, reaching its closest distance, called perihelion, on Jan. 3 at 12:35 a.m. EST. At that time, the Earth will be about 91.4 million miles from the Sun. About six months later, July 6, the Earth will be about 3 million miles farther from the Sun. Remember, the reason for the seasons (I like the sound of that) is that the Earth is on a tilted axis as it orbits the Sun, so the Northern Hemisphere is tilted toward the Sun during our summer, and away from the sun during our winter. There are many excellent illustrations of this online.
Another thing that will continue to decrease, based on climate normals, is the temperature, as the coldest minimum average high and low temperatures occur in January. Caribou’s coldest average high temperature of 19 begins on Jan. 11 and continues through the 28th, while the coldest average low temperature of 0 begins on Jan. 13 and also runs through the 28th. So for both average high temperature and average low temperature, the curve starts upward starting on Jan. 29, reaching its apex (warmest average highs and lows) in July. Caribou’s warmest average high temperature of 76 degrees begins on July 6 and continues through Aug. 9. The warmest average overnight low of 56 degrees begins on July 14 and continues through the 28th.
Back to talking about the Sun, before you know it, you will begin to notice its warmth upon your skin on a sunny day, where you are protected from the wind. The reason the sun’s warmth will become more noticeable is that it will be climbing in the sky, and its rays will be more direct. The sun’s lowest position is about 20 degrees above the southern horizon at solar noon on the winter solstice. By the vernal equinox, the first day of spring, it’s back close to 45 degrees above (about halfway up from being straight overhead), and on the summer solstice, it is about 67 degrees above the southern horizon at its highest point that day.
A fun exercise to do outside with a kid, is to extend your right arms out from your bodies. Raise them halfway up to where you’d be pointing straight overhead (just like raising your hand to ask a question). This “halfway-up” position is about the sun’s height on the first day of spring. Now, bring your arms down halfway to them being held straight out in front of you. This “halfway down” position is close to the sun’s elevation on the winter solstice. Now go back to your first day of spring position, and from there, go halfway to being straight up. This is close to the sun’s summer solstice height in the sky. For more “sun fun”, on a sunny day, go out with a compass and have one of you face northeast and the other southeast. Northeast is the sunrise position here in Northern Maine on the first day of summer. Southeast is the sunrise position on the first day of winter. Without moving your feet, swivel and look at each other and really get a sense of the sun’s changing position in the sky.
I’ll close by bringing it back to amount of daylight, which is how I started this Merry Christmas column, our shortest daylight, on the winter solstice, is 8 hours and 32 minutes, whereas our longest daylight, on the summer solstice, is 15 hours and 53 minutes, a difference of a whopping 7 hours 21 minutes.
No wonder you can get so much more done in the summer.
Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been chief meteorologist at WAGM-TV since 2006. Email him at firstname.lastname@example.org.