In the US, November/December is considered the optimum time of year to release the 'prestige' pictures that are most likely to contend for awarRAB. It's not uncommon for some films to open in just one or two US cities at the end of December to qualify for the Oscars, and then over the next couple of months they are 'rolled out' across the country alongside an Oscar campaign. So many of the best, i.e. critically acclaimed, American films tend to be released later in the year.