Or is it 24 hours, 5 days per week, 52 weeks per year?
I have two people saying that there are no holidays and one that says there are a few. Anyone seeing this mind rating their answers or giving me a link? Thanks!
Thank you all for your answers. Say it is the 4th of July. Would I expect the New York exchange to be closed, while the market remained remained open 24 hours from another exchange? Or would New York remain open as it is electronic, and there would just be lower volume as both bigger players and traders took off?

Thanks for your help.

Answer
Since many holidays are specific to a particular nation, and since FOREX is global, what you could see on holidays is low volume/ high volatility; the nation experiencing the holiday could be taking a break, but other nations not taking that holiday would be trading its currency.

An example of this is thanksgiving or the Japanese new year (which occurs after the first week of January). In the former case, American traders might not be trading, but others would be. And so on, in the latter case.

I do not know of any global holiday that would cause everyone around the world not to trade; except Saturday's.

Are there 24hr foreign currency exchange in Changi Airport?

My flight will arrive past 12 midnight via budget carrier. I need to change US$ into SG$. Does Changi Airport have a foreign currency exchange counter or bank? Do they operate 24 hours a day or at least operate up to 1am?
Yes, I understand it's not good rates. I just want to change enough to pay for the fare from the airport to the hotel.
How about the budget terminal? My flight is Tiger Airways which uses the budget terminal.

Answer
Yes there are 24/7 forex counters in all the Changi airport terminals including the Budget terminal.

RHB Bank is the forex counter operator in Budget Terminal
American Express (+65 6880 1111) and UOB Bank is the forex counter operators in Changi