That's not really a question that makes sense, as I understand it. The forex markets shutdown over the weekend (until 9am Tokyo time, anyway), so there's no-one readily available to take the other side of any trades you're interested in doing. Which means there's no prices to quote...
"The forex market is closed over the weekend for retail traders; however, it never closes because big banks have access to it on the weekends as well.... If a trader wants to open a position on Monday morning or he just wants to trade once a week, then the possibility to be aware of currency rates during the weekend would give him a hint how to arrange his trades."
So in my experience and opinion weekend data is important for both trading early after new week open and for accurate charting. If one want to do some serious work that is.
I used Oanda for checking out weekend movements, but per April 7th 2013 I am not sure if they provide it anymore.
What does it matter? Everyone can understand and agree that if the market opens several hundred pips from the closing rate, new strategies may have to be applied.
