This refers to some of the skills the Snow Jaguar form has. Jaguar Support: "Snow Ressistance Fur" for exsample grants "Water Dmg Immunity" and Jaguar Support: "Playing in the Snow" changes the attack element to Water.
Hope this helps^^
Viewing post in what do i do in the Snow Village boss fight???
Glad that I could be of any help.
As for that, there are several possibilities to further reduce heat dmg. The form you are currently using also can affect the amount. Besides that the dojo has a few optional upgrades to reduce heat dmg. There also is a buyable usable item called Varia Field in town which can reduce heat dmg. And lastly the clothes the main character wears affect heat and cold dmg the most.
i hope this helps^^