This is a follow-up to the best answer linked below:
I've witnessed that phenomenon, recently. The temperature was above zero (probably around 4-5 degrees celsius), and yet I had a thin layer of ice on my motorcycle seat and, more annoyingly, on the road (slippery!)
- the motorcycle was outside
- after the sunset
- it was a clear evening (could see the stars), so there was definitely heat lost to the sky by radiation.
- it wasn't raining. Not sure about humidity though
I still don't get how that water could freeze despite the 5° ambient temperature. More specifically, could anyone explain to me in simple terms (I'm not a physicist):
- why did the water from the air freeze on my seat rather than in the air?
- if heat was lost due to evaporation, how did water evaporate at 5°?
- what provided the energy for the water to evaporate?
- am I missing something?