One of the biggest issues that I’ve had while biking during the pandemic is whether or not to wear a mask. In particular during cold weather, fogging of glasses has been a huge issue for me. The best solution that I’ve found so far is to use a disposable mask with a strip of first aid tape across the nose.
Here is me after a 35 minute commute in about -8°C weather. No fogging.
However, this solution is less than ideal since repeated use of the first aid tape caused skin irritation. There were some positive reviews of a high end mask from Oakley, the MSK3, so I decided to check it out. Note: $74 in Canada.
Here is a user video review showing unboxing, etc, so I won’t bother going through all the details.
His conclusion is that it does a pretty good job of preventing fogging.
However, my experience was quite different, and I imagine it is because I have a relative low nose. Here is me after a ride under more or less the same conditions.
Lots of fogging, just in case you couldn’t tell.
However, as the video above makes clear, it does work for some people.
I have a couple of small notes about the mask. It comes with two filters, one disposable, and the other reusable. They almost look the same; you have to look at the labels on the bag, and also the reusable one has two strips of velcro on the sides.
The other thing is that the replacement filters are also not cheap but I did notice that they were very similar in shape to KN95 masks that are readily available for about $1 each. I’ll be trimming one down to see if it fits.
I will note that the KN 95 mask is quite a bit thicker than the filters supplied by Oakley, and the Oakley mask package has lots of lawyereaze to assert that they make no guarantees about the protective properties of the mask.
Biking in a Big City 
I’ve had good results using a rubber mask frame, easily available on Amazon. It looks like an inverted “V” and fits over the bridge of your nose. I did find that the rubber piece moves around too much and so added a couple of dabs of hot glue to adhere it to my re-useable triple layer mask. I’ve found that using tape works too, until i sweat.
i should have researched more before I bought my MSK3- because for me, I have the same fogging issue. i have a typical flat-nose, round asian head type. Indoors it fairs a bit better, but in the Toronto winter, any glasses I’ve tried on (including many different oakley frames) the mask will start fogging within seconds. 😦
I’ve found that it is a little better if I let it hang as low as possible. Still not ideal by any means
You have to be sure the outer mask is above the filter, and you have to pinch the nose piece of the filter mask in order to prevent fogging. Took me a couple days to figure that out. I LOVE my MSK3.
I did all that and it still doesn’t work well, although it is tolerable if I hang it very low where the cross section of my nose is bigger.
You could try not wearing a mask since you’re OUTSIDE!
Prior to the pandemic, those styles of masks were also useful for outside because not every region has great air quality. So urban riding/etc may have some benefit in that sense to use a mask, with the dual benefit of being used as a ‘mask’ for venues requiring it.
Course in regards to preventing viral contamination, they do not work as well as your typical sterile masks or N95 masks (unmodified/altered). They’re not intended as a Medical PPE.