Dee Burr age 9, of  Burunett, Idaho, for a quest on;

Why doesn’t the coldest day make the most frost on the window pane?

The frost on the window pane is made by bitsy crystals of frozen vapor. This vapor is the gaseous form of water. Water turns into vapor when it ',oils away or evaporates. The air can hold just so much and no more of this invisible vapor. Warm air can hold more vapor than cool air. So! when warm air cools aft;r it has a full quota of vapor, some of that vapor must be unloaded.

On a chilly day, the outside air presses against the cold window pare. This chills the air and forces it to unload its vapor. When Jack Frost is prowling around outdoors, the vapor left on the window pane chills straight into crystals of ice. This is the material Jack Frost uses to paint those delicate pictures of ferns and foliage on the window.

Suppose the day is very, very cold, the coldest day in the year. The air outdoors has already given up most of its surplus water vapor. There is very little left in the air. The colder the day, the less likely there is to be extra vapor in the air. Hence, on the coldest day of the year, Jack Frost has very little, if any, icy crystals to paint the window panes.