Take a clean, soft cloth, cotton or microfiber.

Fill a sink with warm water, and lather up a bar of soap in the sink until the water looks a bit milky.

Dip the cloth, let it dry.

Keep it in a dry pocket when riding. If your glasses start to fog, clean them with the cloth.

The soap residue breaks the surface tension of condensation, so instead of fog you'll get a thin, uniform film of water on the lens. A little bit bleary, but much better than fog. (A tip I borrowed from a North Pacific sea captain who used these on his glasses and his pilot house windows. If you're dealing with salt spray cold enough to freeze, add just a dab of kerosene to the mix and the ice won't stick to the glass.)


If you commute in cold rain for several months of the year, you might want to prepare a dozen or so eyeglass rags at a time, and swap them out when they get dirty or de-soaped.

A helmet with a visor or a cycling cap will keep runoff away from the inside face of your glasses, making the defogging last longer before it needs to be reapplied.