If you're traveling to London don't forget to pack all the right gear: rain coat, shoes that can get wet, an umbrella (though I've heard some people just gave up on carrying one and since storms are usually pretty short. They just wait them out- not my bag baby but whatev).
Maybe that's why all the museums in London are free? So people can enjoy the art while they wait out the storms? I know that's what we usually did when we weren't riding around on the double decker buses so we could at least see the sights while staying dry. The only problem with the bus was, we'd settle in on the top deck and then the windows of the bus would start fog up! Loads of people seemed to have the same idea. You can't really enjoy the views when you have to keep wiping the window clear (at least London has a lot of free daily newspapers so I could use the face of the slime ball Austrian man who kept his kids locked in the cellar's face to wipe the windows- yuck what is happening in the world?).
When the sun finally comes out in London-- stay outside as long as you can!! (I'm obviosly not out there right now...it's not raining but it sure looks like it's going to soon...)