The inside is near room temperature most of the year, but not when it gets down to -20 degrees Fahrenheit (or about -30 Celsius) regularly here. Some amount of ice seems to form on the bottom of the bedroom window any time that the temperature is below around 0 deg F outside.

I did a little research and this seems common in the Upper Midwest climate. R3-rated double-paned windows (which is what I have, I'm pretty sure) can still get pretty cold on the inside when the outside temperature is sub-zero. My heavy blackout shade usage probably further decreases the temperature at the window, since there's no warm airflow across the glass.