[Wauthan]

Extracted from Saber Cherrys "Newbies and Confused People - Look Here!" sticky thread above:

Heat/Cold - For every degree away from a race's preferred temperature, a heat or cold scale decreases tax revenues by 5%, and supplies by 10%. These scales also affects the strength and fatigue of fire and water spells - fire spells generate more fatigue and can be less effective in cold provinces, and vice versa. These scales also affect the stats of and heat- and cold-attuned units (like Summer Lions and Winter Wolves, which get strength, attack, and defense bonuses or penalties). Heat scales also decrease protection provided by ice armors (used by Caelum, for example). Temperatures away from a unit's preferred level increase fatigue in combat (all humans prefer a neutral scale), and cold-blooded creatures are extra-sensitive to this. Lastly, heat and cold scales affect the strength of heat and cold auras emitted by some creatures.

The Heat/Cold scale can vary depending on the season, so keep an eye on the time of year if you use hot or cold units, fire or water magic, or big armies with supply problems.