It was rainy and cold, but my mind was made up. I was walking through this park! Even with the conditions it was worth it, with the added bonus of being completely alone for most of the time. I should add, if you're trying to avoid rain, London may not be your best choice. There is a place overlooking Serpentine Lake called, you guessed it, The Serpentine, to grab a pint and some lunch halfway through. Cheers!