Denver (and pretty much Colorado in general) is the poster child for aridity. This is, naturally, due to its high elevation. The lowest point in Colorado is like 3300 ft above sea level. Even in the summer, humidity values are typically between 25 and 50 percent. If the humidity gets above 60 percent, it pretty much means that it's going to rain soon, because the air just can't hold that much water for very long.
In the winter, the snow is almost always dry and airy. Like we got 3-4 inches of snow here, overnight, that probably would have been 8-10 inches in Denver. I've realized that they salt the roads the way they do here because the snow turns to an oil slick here as soon as it starts to stick to the pavement. This is compared to Denver, where you can just generally plow the roads off, because it's not *that* slick.