During summer, London's bountiful green spaces fill up with office workers and tourists enjoying the surprisingly balmy days as café tables sprout across a multitude of pavements. Due to global warming summer days occasionally become unbearable. The London Underground is not fully airconditioned and temperatures below the surface can be very uncomfortable. Water bottles are recommended.
During winter, the grey skies and rain can be discomforting for tourists. But the famous after-Christmas Harrods Sale attracts a large number of tourists to the city.
Spring or autumn are probably the best seasons to visit the city, when clear crisp sunny days often illuminate London and its landmarks, old and new.