It is now 2015z and 6m WSPR has only been good for locals and GDX here today.
I hear 6m was open to South and Central America earlier (but this was NOT the case on WSPR - no stations active!) and there have been transatlantic openings on SSB/CW. In the past (summer 2007) I have worked the USA on 6m real QRP CW, but I'd really like to spot, or be spotted by, USA or Canadians on 6m WSPR this season. As mentioned before, power is unlikely to be the issue. The main issue will be active WSPR stations in the USA and Canada.