That Charlton 5-2 away game was the coldest match I've ever stood on the pavement outside a ground for, having had a disagreement with a steward on entry and was soon on my way out with an arm up my back (Chaingate, and I'm still grumpy about it today).
Other than that, that Derby game was indeed a chilly one, and in time-honoured fashion I had my hitchhiking boots on. I was at Leicester Forest with snow piled up everywhere on the way back, and there was a truck parked on the slip road. The driver wandered over and said he was on his break, but if I was still there an hour later he'd give me a lift all the way to the M25. Sure enough, one hour later and I was in!
We sped down the M1 because by now it was well past midnight, the road was clear(ish) of snow, and the hard-shoulder was pretty much nose-to-tail with abandoned vehicles. The traffic only got bad once we hit the M25. I eventually got dropped off at the Enfield turn-off and had the interesting experience of waiting for a night bus at 4am in the snow.
The hottest was undoubtedly that Gillingham game, although Wembley last year was a scorcher, along with that promotion thriller at Leicester in 1990.