<P> CFL roster sizes are 46 players (rather than 53 as in the NFL, though only 45 will dress for a game). A CFL team may dress up to 44 players comprising 21 non-imports (essentially, Canadians), 20 imports (almost exclusively Americans), and 3 quarterbacks . </P> <P> The traditional NFL football season runs from the 2nd week of September until late December or the start of January, with the NFL playoffs occurring in January and February . In contrast, the CFL regular season runs from late June to late October . This is in order to ensure the Grey Cup playoffs can be completed in mid-November, before the harsh Canadian winters set in . This is an important consideration for a sport played in outdoor venues in locations such as Regina, Saskatchewan; Toronto, Ontario; Hamilton, Ontario; Calgary, Alberta; Edmonton, Alberta; Winnipeg, Manitoba and Montreal, Quebec . </P> <P> Officials' penalty flags used in the CFL are orange in color . In American football, officials typically use yellow penalty flags . Conversely, coaches' challenge flags for replays are yellow in the CFL as opposed to red in the NFL . Further, in the CFL, the referee wears a black cap with white piping, and the other officials wear white caps with black piping . In American leagues, the referee wears a solid white cap, and the other officials wear black with white piping . </P> <P> Additionally, when announcing penalties, in American football, the penalized team is announced using generic terms ("offense" / "defense", for example), but in Canadian football (especially the CFL) the penalized team is announced by their respective city or province . </P>

What's the difference between the nfl and cfl