This one takes a little maths, but trust me on this. On Jughead's record it says he was born in 2001, and celebrated his 16th birthday in episode 10 of the first season, making it 2017. However, at the 75th Annual Jubilee in episode 13 of the first season, it is stated that the town was founded in 1941 making it 2016. Apparently time is just a construct in Riverdale.