Yeah, not uncommon for building codes/restrictions to vary based on region. Another requirement in a lot of northern regions is the 2x6 studs on exterior walls to allow for more insulation material. Southern regions generally still use 2x4 for exterior walls and most any interior wall will be a 2x4 frame. Also coastal regions have a lot of requirements around windows and such to deal with the tropical storms and such.
Winter of 96 we had 50 some below around parts of the state around the first part of Feb. "Too Tall" Tom Szymanski @ channel 11 threw hot water into the air and it froze in his
weather section of the news. I believe it was picked up by the national news.