Hello. i have Heat and Climate in my modpack and is amazing! but i have a small issue, the frozen lake or ocean won't melt in summer, and it froze in first winter. Am I missing something?

Hello, radum706.
It is currently working correctly. Ice block has the temperature of COLD, and its own coldness prevents melting. However, this specification is unnatural and hinders play. We will improve that in the next update.
Thank you.

Fixed at defeatedcrow/HeatAndClimateLib@a82ee00

it is possible to do the same with the snow? thank you!

thank you!

For snow, it is not subject to HaC system by default config. Please edit "Tick Update Blacklist" in core.cfg and remove snow from blacklist.