Ran a meet in February 1975 in Omaha.
Temps started in the low/mid 20°s and got up near freezing at the "warmest".
Most fun, other than trying to survive, was that the lines melted into the ice before takeoff. We've all seen or heard how wire will sink through a block of ice? It happens.
Start, go to the handle, rip the lines up through the ice, take off and be ready for the damp lines to re-freeze together. Made controls a bit stiff and 'crunchy?'
Racing events were "remarkable" to say the least.
Been there. Done that. Moved to Arizona...