So, There’s No Sun Up There In The Winter, Right?

It seems that nearly every conversation I have with overseas family and friends this time of year where Iceland is mentioned ends up with them saying something along the lines of, “Yeah, but it’s dark all the time there now, right?” It becomes clear that they picture it such that, for three months of the year, Iceland is the land of the Mole People, with its human residents stumbling around in pitch blackness or shining flashlights to keep the grues away.

The Reality Is Surprisingly Complicated.

Most people from lower latitudes picture distinct time periods, “day” and “night,” and think of the transition time as relatively insignificant. They also tend to picture day length by season. But neither of these concepts really apply well at a latitude of 64 degrees.

First, to go from “constantly bright” to “lots of dark” over the course of a year, day length has to change fast! In early November, we lose nearly seven minutes of direct sunlight per day. It’s enough that people with punctual schedules and a south-facing window can readily notice the decline every day. One starts November with eight hours of direct sunlight, but by the low point in mid December, it’s down to just over four. But then by the end of February it’s over 10 hours. So simply talking about how much light there is in the “winter” doesn’t give a sense of how much it varies, even day to day.

Then Comes The Issue Of, “What Do You Mean By ‘Dark’?”

Just because the sun is below the horizon doesn’t mean that it’s suddenly pitch black. Now, if you live in a place like Miami, sure, there©s not even half an hour between “it’s bright enough to see what I’m doing” and “the sun is blazing in my eyes.” But up here near the Arctic Circle the sun doesn©t go as much overhead as take a low broad arc. In the summer, it arcs all the way around you, rising in the north and setting in the north. In the winter, it barely pops up in the south and sets again just a bit further west in the south. That “in-between time” gets really stretched out.

Day and night are divided into different categories based on how low the sun is and how much light is out: astronomical twilight, nautical twilight, civil twilight, and direct sunlight.

Astronomical twilight is where there is not enough light in the sky to see much of anything on the ground, but it lights the sky a little bit and blots out faint stars like having a second moon up. During the solstice, Seattle and Paris get about 12 1/4 hours that are this or brighter. Reykjavík gets just under 11 hours. That’s right, the night sky at the winter solstice is completely dark only 10% longer in Reykjavík than in such cities!

Nautical twilight is where it’s bright enough to clearly see the horizon, but not yet bright enough to do everyday activities. Seattle and Paris are at least this bright for 11 3/4 hours, while Reykjavík has 9 hours of it. So we get over three fourths as much “horizon glow” at the solstice.

Civil twilight is where it’s bright enough to do everyday activities but the disk of the sun is not yet up. Seattle and Paris have 9 1/2 hours; Reykjavík gets 6 3/4 hours, or just over 70% as much.

Finally there’s what a lot of people only care about: direct sunlight. Paris and Seattle get 8 1/4 while Reykjavík gets just over 4 hours, or only half as much. But it gets worse because while in the former cities the sun rises to an 18-degree altitude, here even in the southern side of mountainous Iceland it doesn’t muster three degrees! The most minimal of mountains can block most to all direct daylight, while any low clouds can easily turn the sun into nothing more than a fuzzy haze. Some small towns in Iceland get no direct sunlight for months on end.

So to sum up: it’s absolutely true that we don’t get much direct sunlight in the winter, and around the solstice, there’s barely any. But we do get a surprising amount of “dim.”