So much sunshine to the square inch


Some people are so much sunlight to the square inch. I am still bathing in the cheer he radiated.

We spotted this quotation by Walt Whitman painted on the wall of a neighborhood school here in Boulder, Colorado this week. Beyond the vivid description of the effect of one person on another, it's a neat encapsulation of what insolation is all about.

In terms of feelings of good cheer generated by the people you spend time with, it's probably a reasonable assumption that more is better. But with actual insolation? It depends...

Often, insolation correlates with temperature - the "hotter" the sun, the hotter the air, but this isn't always the case. Anyone who has climbed mountains or even hit the ski slopes can attest that it may be very cold at the same time the sunlight is notably intense. The higher above sea level you get, the thinner the atmosphere, and the more powerful the insolation. For example, ascending ~9,000 feet from downtown Boulder to the summit of nearby Longs Peak results in a ~6.5% increase. But you'd probably want to pack a warm coat too.

Another famous phrase associated with power of the sun comes from Noël Coward's 1930's song "Mad Dogs and Englishmen Go Out in the Midday Sun". As he explains:

In tropical climes there are certain times of day When all the citizens retire To tear their clothes off and perspire. It's one of those rules that the greatest fools obey, Because the sun is much too sultry And one must avoid its ultry-violet ray.

There's a great article here explaining the background to the phrase, suggesting that it may originate from a book describing the behavior of Englishmen abroad in 18th-century Venice on the Grand Tour.

You might think avoiding the midday sun generally applies only during the summer months, but it depends what you're planning to do. If you were sat outside the south-southeast facing cafe here in Boulder (a little farther south than Venice), you'd get twice the sun exposure in December than in June during the mid-day hour:

December midday insolation

Depending on how much you love the sun on your face, that might be a good thing or a bad thing. Topping up on Vitamin-D? Great. Working on a laptop? Not so much. Either way, you probably need the blinds drawn to avoid the winter glare indoors.

With sunshine, as with so much in life, the Goldilocks principle applies!