Packing Tips for Your Trip to London
Does it rain all the time? Absolutely not. London is, in fact, on the dry side of England.
That said, it is likely to rain at some point during your trip. You should pack an umbrella or a lightweight slicker in spring, summer, and fall. In winter, take a heavier rain coat. (In Britain, rain coats are called "macks", not "slickers." Separated by a common language...)
London tends not to have extremes of temperature in either direction. If temperatures touch 80, it's a heat wave - that said, summer often sees weather in the seventies, and you will want short sleeved shirts and a short skirt for girls. Winter weather tends to hover around or dip below freezing. Extreme cold is unusual and London gets relatively little snow. A light coat and a sweater should be enough.
Do You Need To Dress Up?
London is one of the few cities in Europe in which the answer is no. You can get away with jeans and a t-shirt in most situations, including casual restaurants, although a button-down shirt may make you look less "American." (For fine dining, though, you will need to dress up).
Taking a nice set of dress slacks and a button down shirt is a good idea, however. Classical concerts, operas, and very expensive restaurants all require you to dress up. Some higher end night clubs have a "no jeans" code. Black tie events follow the same rules as in America and daytime formal is often called "white tie."
England is on the 220 volt system. Check any electronic devices you plan on taking. Most new devices and almost all computers do not need voltage converters. An older MP3 player or camera battery charger may. You will need a step-up voltage converter, which you can get at Radio Shack or another electronics store.
For all devices, you will need a plug converter, which can also be bought at electronics stores. Be aware that if there is a plug in the bathroom it may be on a low wattage circuit. Don't plug hair dryers into sockets marked "shaver only." It's not good for your device at all.
You definitely want to pack your camera, or your smartphone. (Cameras are better for long trips as they have much better battery lives than phones).
Getting At Your Money
It used to be that you needed to get travelers' checks. This is no longer true. Your U.S. bank ATM card will almost certainly work in at least some ATMs in London. (Avoid using your credit card - most European ATM machines don't take them and if they do, credit card companies charge higher transaction and conversion fees).
If somebody tells you your credit card won't be accepted - they're lying. All manned point of sale terminals in the U.K. can handle U.S. magnetic strip cards. The clerk might not know how to do it (I've had to teach them how before). Unmanned vending machines and ticket machines, however, may not. Don't bother with a reloadable chip and pin card unless you plan on taking a lot of trips to Europe - they're expensive and rarely necessary.
What Else To Take
1. A comfortable pair of shoes. Driving in London is a nightmare - let the cabbies do it and enjoy the city's wonderful public transport network. For shorter distances, walk.
2. A small daypack to carry all your various stuff. Having everything with you means you don't have to go back to the hotel.
3. All of your paperwork. A photocopy of the relevant pages of your passport (leave it in the hotel safe), copies of all receipts, etc.
4. All prescription and non-prescription medicine you need. You may not be able to get the same OTC medicines you are used to.
5. Ear plugs. Especially if you don't live in a big city. London sleeps as much as New York does - never. If you're used to noise all night, you'll be fine. If you aren't, then you may appreciate them.
6. A travel pillow. You'll want it on the redeye you're taking over (there are pretty much no flights from the U.S. to London that are not redeyes).
7. Camera, cell phone, e-reader and travel adapters (if needed). At least one plug adapter per person going on the trip. At least one extra memory stick and at least one extra battery for your camera.
8. At least one nice outfit - slacks and a button down shirt are usually fine for both sexes, a suit or dress if you're planning on going to something really posh like the opera or the symphony orchestra.
What NOT to take
1. Hawaiian shirts. Do not wear Hawaiian shirts in Europe. You will not just be noted as an American tourist - you'll be immediately branded as the bad kind of American tourists.
2. Fanny packs. Thieves call them one stop shopping. If you do like them, don't put money and documents in them. And don't call them a fanny pack. In the U.K. they are called "bum bags." Really don't call it a fanny pack. The word "fanny" in the U.K. does not mean what you think it does...
3. Slogan T-shirts. Same note as Hawaiian shirts. T-shirts with pictures on them are fine unless you're dressing up, but slogans will tend to brand you as a tourist. Plain T-shirts are the best.
4. Shorts. British people only wear shorts on the beach or to work out. Even if you hit that 80 degree heat wave, no shorts.