window question

Maybe warm air going through uninsulated wall and air leaks in frame.

Well I would suggest that those storms are not very well sealed. In any case the window is below freezing. The plastic keeps the warm room air from warming the primary window so it is staying below freezing. Now add enough moist air from inside to get to that primary window and you get ice.

Even though the air in side may be low humidity, it is not likely to be low enough not to condense and freeze on that primary window.

Without the plastic you would likely have cold wet windows. Without the storm windows, it would be what you have now, only worse.

The comment about the air leaking though the walls has merit.

It's winter?

ummmmmm.... cause it's cold outside and snowing?

just a maybe...

HE SAID! the ice was on the outside... That's normal. duh.

I am having problems with OP's comment about the frost is on the outside of the storm windows. Frost on the insides of the storm Windows, yes I can come up with several standard answers. But on the outside of the storms?

I keep thinking of old broken down window glazing putty is leaking cool moist air from around the edges on panes of glass. I thought that leak is supposed to be stopped by that small thin bead of glazing compound that is put down in the sash rabbit before placing the glass into the rabbit. I could be wrong.

Looking for additional comments from group as could be educational thread.

"Phil Again" wrote

Normal. It's winter. If well sealed, the only ice will be on the outside. If there are air leaks, it would be on the inside and the inner window. If really bad leaks, it would be on the inner inside window and drip into the house.

In fact, it sounds like he's properly insulated enough that the only ice is on the outside and the warm inside air isnt getting across to melt it.