Greater London in September

April through September gives you the best weather odds, but London's unpredictable. I've seen snow in April and 25°C in October. Pack layers always. May and June are sweet spots — long daylight hours, Hyde Park's in bloom, and outdoor theater season starts. But everyone knows this, so book accommodations early. July and August bring crowds and higher prices. The Edinburgh Festival empties London of performers, but you get outdoor cinema in parks and the BBC Proms at Royal Albert Hall. September's underrated. Weather's still mild, summer crowds thin out, and theater season kicks off properly. Plus, London Fashion Week brings energy to the streets. Winter has its charms. Christmas markets, shorter queues at major attractions, and cozy pub sessions. But daylight runs from 8am to 4pm in December. The Christmas lights on Oxford Street go up in November and stay until January — pure magic on a foggy evening.