Question

Why do we see water droplets on the outer surface of glass containing ice cold water?

Answer 1

Due to condensation: The water vapour present in the air around  the surface of the glass of cold water gets cooled down and converted to water droplets.

Answer 2

there is water vapor in the air which on contact with the cold glass becomes just plain water and sticks to the outside this happens many times and eventually droplets form in fact a cooling device is one way to get a clean source of water from an enviroment with unhealthy groundwater