A: The short answer is that objects can radiatively transfer heat to the very cold night sky on a clear night.
The longer answer includes consideration of conductive and convective heat transfer from other materials in contact with the water, and energy changes associated with condensation/evaporation and freezing/thawing.
You may find Dr. David Kilty’s discussion of radiative heat transfer, “How to Freeze to Death in Wyoming in the Summertime,” informative and entertaining.
A: The short answer is that objects can radiatively transfer heat to the very cold night sky on a clear night.
The longer answer includes consideration of conductive and convective heat transfer from other materials in contact with the water, and energy changes associated with condensation/evaporation and freezing/thawing.
You may find Dr. David Kilty’s discussion of radiative heat transfer, “How to Freeze to Death in Wyoming in the Summertime,” informative and entertaining.