It is normal for regular eyeglasses to get foggy lenses because of the change of weather. Usually, the lenses can fog up in very cold place or in high temperature place. But luckily, there a type of anti-foggy coating that can apply to eyeglasses lenses. If you don't want to be bothered by foggy lenses, you can have an optician add anti-foggy coating to your lenses.
This is a normal physical phenomenon that when vapour meets the cold object, the vapour will condense to be water on the surface of the cold things. It is possible that the temperature outside is hotter that the inside, and your cold glass lenses will get condensed vapour when you go outside. You can use glasses cloth to muffle the glasses lenses in your palms for a minute, then wear the eye glasses and go outside, so that there will not be great temperature difference and that the vapour will not condense on the glasses lenses.
As you know , it's warmer outside now . When the temperature of the rooms you stay is colder than outside , your glasses are colder than that , too . Some steam in the air would liquefy and become small droplets when it comes across with your cold glasses , that's the fog .
It's just the same reason why your glasses fog up when you are eating some hot food .
Just like taking out a bottle of water out of refrigerator it would fog up. Your glasses would also fog up if the temperature indoor is lower than outside. Getting a pair of anti-foggy coated glasses may help.