Hertz tells me that peak dates haven't been finalized yet, but since redemption kicks off June 1, they should be forthcoming very soon. The way I understand it, off-peak dates are most days of the year, and peak dates will function in a similar way to airline 'blackout dates'. On these blackout dates (or 'peak dates'; they're the same thing), a rental will simply cost 1200 points instead of the usual 600 points.