[Revvin 911S]

There is no such thing as an "official" exchange rate. By law, the US has a floating exchange rate. This means that it is market driven, so depending on the supply of and demand for our currency v. the same for the foreign, the rate can change at any given second.

For example: A foreign country, lets say Britain, offers a return on government securities that is 1% higher then domestic rates. This will stimulate US investors to invest their money in Britain to take advantage of the high interest rates. In order to do this, the US investors need to buy pounds, so they supply dollars, and demand pounds. This affects exchange rates, making pounds relatively more expensive since there is now an increase in demand for pounds, and an increase in supply of dollars on the foreign exchange market. Your dollar now buys fewer pounds. This is happening all day, and people get paid large amounts of money to stare at a computer all day tracking these changes, and purchasing or selling in order to make money. You will not be able to keep up with the professionals. As stated before, just go and have a good time, and try not to think about how badly you are getting "screwed". If you have a good time, that is worth losing a little bit on the exchange rate.