LOL Katielou! So, the secret's out. Hey, I have sort of turned into a fair weather hiker too.
Here's something that's a pretty good read with cool pictures to describe the rain shadow.
http://www.seattlerex.com/life-in-the-olympic-rain-shadow/
Romy, I didn't know this, but Olympia is also in a rain shadow, a different one, caused by the Black Hills.... but there's a lot more rain there than Seattle. But you probably already know this. And you get a ton more rain though, than Seattle. I didn't realize that until fairly recently. It's funny how Seattle has such a reputation for "all that rain," when in reality, there really isn't that much in inches, just that it's a little on the moist side a lot of the fall and winter, and spring. LOL
Here's another interesting thing that describes more about the rain shadow effect. Sequim has very few inches of rain, yet isn't like a desert in that there is still a lot of green trees like most places around here. It explains why. It is the lavender "capitol" of the country. They grow a ton of it and lavender likes it dry.
http://www.oregonphotos.com/Western-Washington-rainfall-1.html