We have the exact same temperature bonus in the mountains as in the taiga. The fact that the effects would be the same are thus logical.
Forever Frost will solve these two issues, and give us a combat advantage by turning the climate cold, which favours us northern folks.
Except it won't.
We used forever frost in the Jungle before, and it accomplished nothing of note.
Let's remember, this was the description of the Moskurgian cavalry.
Calvary, the heavy artillery of the medieval era, were once limited to minor nobles and knights. Restricted to critical battles and the relatively less-risky skirmishes that preceded them, most combats have consisted of boots on the ground slugging it out. This does not seem to be the case for Moskurg, however; their horses, seemingly only fit for travel and not combat, are...everywhere. Though lightly armored, entire divisions of the troops have crashed into our battle lines over and over again, snapping their shoddily made lances and lashing out with sword and spear. We fail to win a single battle here, let alone gain a territory. Those who aren't run down quickly surrender, and once relieved of their armor and weapons are immediately returned to us. Our own cavalry are much stronger than any Moskurg horseman, but even they can't win against a seething ocean of these overgrown rats. Fireballs blast holes in their ranks, but they're filled as soon as they appear. Horses leap through walls of flames, and though a few tumble from their saddles wreathed in fire the rest charge through our ranks like demons. If we do not do something to counter these new horsemen, we may very well see their hoof prints on Arstotzkan home soil.
Enormously good and effective, despite their shitty quality.
We have better armor, better weaponry, and better horses for this kind of combat. We would crush the Moskurgians.
Meanwhile, this was what our frost tower did :
A bolt of lightning crashes down into the tower not a few feet from where Myark was standing. The explosion of super-heated plasma sends him and the stone bricks he was standing on off the side, and they all come crashing down into the foliage below. The sudden disruption of the delicate, carefully-drawn spell circles on the roof of the tower resulted in a second, much slower explosion. Were Myark still standing atop the tower he might have been able to prevent the cook-off of magical power slowly growing out of control, but without him there was little the wizards left could do. The top of the tower flashes briefly.
The explosion sends mortar, brick, and bodies sailing into everyone standing around the tower with an indiscriminate violence. Unfortunately, it was mostly Arstotzkan troops standing nearby. Plate armor absorbs a good portion of the debris, but with their hero wounded and most of their mages dead the troops have no option other than to retreat. Myark is hauled off the battlefield by one of the surviving squads, and they manage to abscond with him. He will live.
So, it did not stop the storm amd it did not stop the lightning. It's basically a piece of crap more harmfull to our own forces than to the enemy.
I'm open to redesigning it, to make it better and more usefull. But as it is now it's useless.