Ritteri anemone “Heteractis magnifica”

Why and when does condensation form? Learn to avoid temperature changes. One final important tip to prevent snorkel mask fogging. Condensation happens when the temperature of the glass is lower than the air inside the mask. Basically that means that when you go from a hot environment to a cold environment. So when you have had your face in the water, and then come up and face the sun, the hothouse effect warms the air inside, and then when you plunge it back into the colder water the glass will quickly cool, and condensation will form. So when you are sitting up in the water to talk with your partner, or when you first put your mask on, make a habit of turning your back to the sun.