It costs £24.95 for the privilege of riding the lift to the top of the Shard. If i'm going to sink that much cash into a view, I damn well want to be able to see the Queen for that price. Failing that I want a graph telling me how much money has been wasted by "inclement" weather.
This page says that for each day the shard is in cloud it costs an owner of a penthouse flat around £8000.
Visibility over the last 24 Hours:
Thick black line denotes no visibility.