London is a majestic, royal city, full of elegant palaces and monuments that once marked the center of a global empire. It's also a modern, edgy city, full of museums, dance clubs and boutiques that set international trends. The one thing that London doesn't have in October is predictable -- or especially nice -- weather, so your packing list should prepare you both for a wide variety of activities and sudden weather changes.

Precautionary Dressing

In October, London weather ranges from cold to dreary. Average temperatures range from the high 40s to the high 50s Fahrenheit, and you should expect light rain most days. London fashion is more casual than many European capitals, but still more elegant than casual U.S. dress. Especially if you're not used to the cold, bring long pants or dresses and a few sweaters or light jackets. Jeans are OK in London, but keep your clothing simple and avoid baggy or heavily branded items. Londoners tend to dress in dark or neutral colors, so limiting the colors in your wardrobe will help you fit in and combine items on different days to save space in your suitcase.

The Extras

If nothing else, bring an umbrella. You'll want to carry it with you everywhere, so pick a small, portable one. London is a walking city, so a comfortable pair of shoes will come in very handy for sightseeing. Don't forget a good rain jacket for sudden downpours; a scarf and wool hat can keep you warm when the mercury dips. Lastly, bring at least one dressy outfit for a nice meal or outing. As in the U.S., suit and tie or a dress will be enough for most high-end restaurants and events, but some gallery exhibits or very exclusive establishments may require cocktail attire. The British Film Institute has its world-famous yearly festival in October, and many film openings are gala events.

Getting Connected

In the modern city of London, a few electronic devices can make your stay much more comfortable and enjoyable. In addition to whichever electronic devices you usually use -- such as an MP3 player -- a smartphone will help you stay in touch with folks back home and keep a pulse on this lively city. The annual Frieze Art Fair is in October, attracting thousands of international art buyers and prompting unmissable events, talks and exhibits in many of the city's galleries and museums. You should have no trouble finding a Wi-Fi hot spot to check the latest event listings. Lastly, foggy London makes for great photos, so bring a camera. Just remember that English voltage and outlets are different from the U.S.'s, so make sure your devices are compatible with 230-volt current and bring a universal travel adapter.

Odds and Ends

To get to the red tape first, you'll need a valid passport to enter the U.K. While U.S. citizens do not need a visa, you may be asked to provide an address in London or show proof of a departure date, so keep your travel itinerary on hand at the airport. Other than that, bring along any comfort items you usually bring on trips -- like a good book or few favorite snacks from back home. Binoculars can help you get a better look of the dome of St. Paul's or the gilded ceilings of London's royal palaces. The London Restaurant Festival is also in October, so bring along a good appetite. Even if English food isn't that remarkable, the city's many restaurants serve up exciting international fare and a few interesting twists on local classics.