The low of five this morning wasn't just the coldest so far at MW this season, but it's also one of the coldest readings this season in the lower 48:
Oct 5: 0 at White Mountain, CA
Oct 6: -1 at White Mountain, CA
Oct 22: -3 at Hohnholz Ranch, CO; -1 at Shirley Basin, WY; -1 at Walden, CO; -1 at Gould, CO; -1 at Lake George, CO; 2 at Antero Reservoir, CO; 5 at Fraser, CO; 5 at Bailey, CO
So outside that one very cold morning in Colorado, that 5F reading is only behind White Mountain, CA, for coldest reading this season. White Mountain recorded 0F on a day in June earlier this year!
By the way, the coldest temp recorded in Alaska so far is -26 at Arctic Village, on Oct 26th. It was -20 this morning at Chandalar Lake!