As a precaution, ensure a safe driving by installing highly-efficient and powerful fog lights and try to maintain a regular windshield and mirror cleaning program. However, addressing to your specific query, you should lower down the inside temperature of the car to ensure that the moisture stops to condense on the glass. Additionally, you can open the windows or defrost the vent without heat, which can dissipate the fog very fast. I always try to keep the windshield and mirror clean that helps to prevent the accumulation of fog on a further note.