The most dramatic happening in the sky these days is not unfolding at night. It’s in the day. And it affects all of us, big-time.
Many assume that the change to warmer weather is due to the Sun being out longer and longer—the growing change in daylight length. That’s partially true. But the biggest factor in our transition to spring is the height of the Sun.
Never stare at the Sun, of course. But many of us take quick squinting glances to see how high up it appears at Noon. Two months ago it was pretty darn low from everywhere in Canada, Europe, and all of the United States except for the south. But check it out now. It’s dramatically higher.
The next two months brings the year’s most rapid change in midday solar elevation. The Sun keeps getting higher in the sky at noon, increasing the distance it appears to be above the horizon.
To use real numbers, let’s assume you live somewhere around the typical 40 degree latitude of Philadelphia, Columbus, Indianapolis, and Denver.
On February 26, the noonday Sun is 41° high.
Less than a week later, on March 3, its 43° high. That’s four Sun widths higher up! In just a few days!
On March 21, the first full day of spring, its 50° high, or roughly 20 Sun diameters higher than it is right now. The practical effect of this is to make the solar rays noticeably more intense. You can easily feel the difference on your skin.
A quick demonstration of Sun angle involves aiming a flashlight at a white surface. If you point the beam straight onto a wall it shines at its brightest. But aimed at an angle, the light is dimmer. If you make the angle very pronounced, by holding the flashlight flat against the wall, the light’s intensity is greatly diluted.
Same with the Sun. We’ve been living with diluted sunshine since late October. But the next eight weeks sees the year’s greatest solar intensity alteration. It’s a big brightness boost for we who live in the northern hemisphere, and the greatest annual diminishing for our Aussie and Kiwi friends. Those with solar panels will see the change too, in the numbers displayed on the meter.