The coastline is subject to a wide variety of weather from coastal advection fog to local seabreezes that develop with the daytime heating. In Florida, the seabreeze front often signals the beginning of those famous summertime afternoon thunderstorms. In California, on the other hand, an afternoon seabreeze will usually just cool off the beaches while the valleys a few miles away continue to bake in the afternoon sun. As for the fog, rising terrain will usually stop its inland progression. Interestingly enough, the exact opposite often happens during the wintertime.
Mountains can help turn good weather into bad, and can make bad weather even worse.
You just have to be aware of the dangers and look for the warning signs. Cumulous clouds developing along ridges and mountain tops signal turbulence, updrafts and unstable air. Even more dangerous is the mountain wave. A mountain wave can be best described by imagining you in your airplane as the wind. OK, you're buzzing along at 8,000 feet doing 120 knots when all of a sudden, there's a 12,000 foot mountain ridge dead ahead.