Considering how temperate the London climate is, it’s amazing how much mileage the locals get out of the subject. The truth is that there’s no best time to visit London – summers rarely get really hot and the winters aren’t very cold.
In fact, it’s impossible to say with any certainty what the weather will be like in any given month. May might be wet and grey one year and gloriously sunny the next; November stands an equal chance of being crisp and clear or foggy and grim.
So, whatever time of year you come, be prepared for all eventualities, and bring a pair of comfortable shoes, as, inevitably, you’ll be doing a lot of walking.