Weather Blog

Tired of the rain? Here is one place where it never rains

Tired of the rain? Here is one place where it never rains

It's yet another soggy holiday weekend in Seattle, where we feel lucky when we go a week without rain. In the Desert Southwest, sometimes dry stretches can last a month or two.

But if you truly despise rain - I mean, you're a snowbird, and still consider Tucson to be too wet -- have we got the place for you: The Atacama Desert, situated on the west-central coast of South America.

How dry is it there? Many sections of the desert can go *decades* without receiving rainfall and according to this article in the BBC, some measuring stations having never, ever recorded a raindrop. (Yes, even on three-day weekends.)

Here is a chart of rainfall at Iquique, which is closer to the coast and not in the center of the driest part (they sometimes get some drizzle whipped up by weak fronts) but this gives you an idea of how rare rain is. (1 mm is 0.039" of rain)

Why so dry? There is a unique confluence of topography and meteorology. First of all, you have the Andes Mountains to the east of the desert, which stretch well over 20,000 feet tall in spots. And you have a range of mountains along the Chilean coast to its west. Trade winds blow mainly from the east and as that air ramps up the eastern slopes of the Andes, the moisture gets squeezed out -- thus the Amazon rain forest. But on the flip side, that dry air gets even drier when the air sinks down the other side of the mountains.

But even when the weather comes from the west -- the coastal range mountains also soak up all the moisture. So no matter which way the weather blows, the moisture is getting obliterated before it can reach the desert.

If this sounds familiar, it is very similar to what drives our Olympic Rain Shadow and makes Sequim not quite a desert, but at least relatively dry -- predominant southwest winds that get their moisture wrung out by the Olympic Mountains.

Now, if you happen to make it up there, you'll find some sparse - but not zero - vegetation. It turns out some moisture can be delivered on rare occasion by some marine fog blowing in off the Pacific (gee, that sounds familiar, too.)

So next time you're feeling a bit soggy, know there are some places that would probably gladly take the rain off our hands for a day :)