I drove to Brighton away (from Surrey) last year, only to find out when I got to the pub before the game that it had been called off due to fog, but I'm sure that when I lived in Cardiff, a home game against Milwall was called off on our way to NP. So, a lot less than an hour before KO, as I lived in Lakeside. It must have been late 1970s? Maybe even one of the very first matches scheduled for a Sunday?