Tomorrow, Friday, 3rd July, is a major public holiday in the U.S.A. This year, the 4th of July is effectively the 3rd of July, 2015.
Note however that it is not a public holiday anywhere else in the world, so the global Forex market should be relatively unaffected. As the U.S.A. is one of the major financial centers driving volume in the Forex market, we can expect this day to have levels of volatility and price movement somewhat lower than would be usual. Additionally, this holiday falls on a Friday, so it is likely to form part of a “long weekend” and cause the markets to get things wrapped up as much as possible before the day, particularly as the key non-farm payrolls data release in the U.S.A. will be held one day earlier than usual, on the day before the holiday.
For these reasons, we do not recommend opening any new trades in USD pairs whatsoever after 1pm Friday London time, until 8am Tokyo time the following Monday, 6th July. It is of course acceptable to close trades during this period, as if a stop loss is exceeded during such a relatively slow period, it would be very likely to also be exceeded during an active market. Trades in non-USD pairs can be taken as normal.
Please be aware that most retail Forex brokers will allow trading during normal market hours tomorrow, Friday, 3rd July. Those based in the U.S.A. may only offer somewhat curtailed customer support. If your broker is located in the U.S.A. and you can possibly wait or avoid requiring active support from your broker over this period, you should eventually receive a more prompt and convenient service on the following day.