Sometimes during cold times in winter, frost flowers forms indoors on the window glass. Explain a) under what conditions of humidity and temperature that may happen and b) why this is occurring indoors on the glass rather than on the outside.

Sometimes during cold times in winter, frost flowers forms indoors on the window glass, 

under what conditions of humidity and temperature that may happen ; 

• During cold times in winter, indoor air is a lot hotter and holds more dampness than outside air, which is colder and dry. Warm, sticky/humid indoor air cools and agreements/contracts; as it contacts the cooler windows, the dampness/moisture consolidates/condenses on the glass. 

why this is occurring indoors on the glass rather than on the outside; 

• Buildup regularly happens on cooler surfaces inside the home, like astragals, pivots, equipment and glass. These surfaces are cooler since they are nearer to the outside than a divider or table, and abundance dampness condensates on these surfaces. The dampness noticeable all around is characterized as moistness.  
• The motivation behind why the interior buildup happens depends on various variable factors that are out of the window fitters' control. The dampness/moisture is noticeable all around inside the room/building and not in the windows/glass. Factors to consider include: moisture arising from the dwelling from; cooking, bathing, poor or no ventilation, no trickle vents and never opening windows to allow air circulation.

Step-by-step explanation

El Diasty, R. and Budaiwi, I., 1989. External condensation on windows. Construction and Building Materials, 3(3), pp.135-139. 

Werner, Anna, and Arne Roos. "Condensation tests on glass samples for energy efficient windows." Solar energy materials and solar cells 91, no. 7 (2007): 609-615.