Why do we see water droplets outside of a cold glass - Reasons

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

The image you see outside the glass is not a water droplet but a result of very small fog droplets that have frozen on the surface of the glass. Water vapor in the air condenses on whatever surface it touches, be it window glass or other objects. 

The surface temperature of the glass is colder than the temperature of the air outside and below the dew point of the water vapor in the air. As water vapor cools, it condenses into tiny water droplets that form fog. 

In order for these droplets to freeze, they require a nucleating site. Dust particles or even water vapor molecules can serve as such a site. The water droplets that you see outside of the glass are the result of these droplets landing on the surface of the glass and freezing.