A "hot" metal cover in the snow

 

It snowed yesterday morning. All morning, the snow refused to settle on this access cover for the drains. Metal feels cold to the touch so this seems weird. However, metal feels cold because it conducts heat well. The air trapped in the drain space will have been warmer than the air above so conduction will have been from below. This will have been enough to melt falling snowflakes. The ground around is loose and traps air. The trapped air acts as an insulator so cannot conduct from potentially warmer ground below. It's interesting that people talk about "stone cold" which suggests that rocks could also be good conductors.