Exterior painting in cold weather

Primer dries fast, so 50's will probally be OK, especially if it gets some direct sunshine. Give it some time however, before painting. I have used exterior paints as low as the 40's as long as night time temps are not going much lower, or paint/primer at least 4 hours before temps drop a bit. Some paints do give a temperature range. There are low temperature paints that will cure down to upper 30's with no problem. The main problem with priming or painting in cooler temps, is that you must let it cure enough before applying the next coat. That may take a couple of moderate temp days as it will not cure in the colder nights, dew or excessive moisture, as that will delay the curing process or discolor the finish.

I personally would use it, presuming I'm going to top-coat it with exterior paint. Of course, the very designation of the primer as "interior" means that the manufacturer did not INTEND for you to use it outdoors. So you're taking a chance.

But I'd do it and not give it another thought. What's the potential downside? Probably something like "If it doesn't hold up, you'll have to repaint the glazing in a year or so..." I can live with that.