OK, there were NO cold inducing effects anywhere on the battlefield. Having looked at the replay again (for the Last time!) I see that while yes they did have undead, none of the undead came near my mages. And these were simple undead (longdead, etc) no wraiths or other things, they were lead by an evil priest (simple one) the only spells he cast during the game were unholy protection. Yes I know I did say my mage cast spells, but I was mistaken, since i had 3 spell casters and got mixed up with the names.
Once he was at 131 fatague, I noticed he jumped to 163 fatigue the next round (then back down to 154, gets 9 fatigue/round??), then the one after jumped to 200, and back down to 193.
Here are some pictures (forgive the size, yahoo has been a real weenie as of late with photoalbums requiring you to pay to see a real sized picture)
http://tinyurl.com/zbhn
mapheat - a picture of the map province, as you can see the terrain is Heat 1, not cold.
begincomb - troops are running to kick some tail
131fatcom - picture of combat when I was at 131 fatigue
131fat - picture of the guy I'm talking about at said fatigue, I dont see any icons that might suggest any status ailements.
200fat - picture when he spiked to 200 fatigue
193fatcom - right after when he dropped his 9 fatigue again and proceeded to die shortly after, as you can see all the armies are routed, nothing is near me, they're running away.