How cold is cold? :-) Water below ”sea” level tends to stay around -1C (salt water) to 4C. Below that, water becomes ice… Ambient temperature can drop to -40C

How cold is cold? :-) Water below ”sea” level tends to stay around -1C (salt water) to 4C. Below that, water becomes ice… Ambient temperature can drop to -40C … internally these ice blocks hoover around -10C.