London has notoriously fickle, at times inclement weather. King George infamously referred to the English summer as "three fine days and a thunderstorm." But don't let a little rain put a damper on your trip! Pack thoughtfully and dress smart and you'll be just fine.
Layers, layers, layers.
London weather can shift dramatically a few times in a day. As such, you’re going to need a variety of clothing options to accommodate whatever climate you find yourself in. Pack neutral clothes that can be easily layered.
From December through March bring plenty of cozy, warm clothing. Winters are quite chilly. It’s not uncommon for it to snow in April either. Pack gloves and a hat that covers your ears. Wear high shoes or boots to keep your feet warm and dry. Leather or waterproof is best.
May through August you should be safe with summer clothes, but pack some sweaters and a jacket with a hood for drizzly weather. Skip the sandals - they’re miserable in the rain and you’re probably going to be doing a lot of walking. Wear comfortable sneakers (“trainers”) or otherwise.
Leave the umbrella at home. They’re less useful than hoodies and will take up too much space; besides you can very easily pick one up around town. Check out J. Smith at 53 New Oxford Street - they’ve been selling umbrellas for over 150 years. They’re also readily available (and cheap) at any London high street shop.
And don’t worry! If you forget to pack something remember that you’re in one of the fashion capitals of the world. There’s fantastic shopping everywhere, so you are sure to pick up some neat items for your trip (and to take home!).