I wore one on my last hike -- and in fact, the hiking trail was the most crowded place I've been in months. Parks all over the US have seen record-breaking attendance figures this year.

In the SF Bay Area, where the hiking is amazing, the majority of people I see are wearing masks. We also have some of the lowest incidence of Covid in the US for the density and population.

Personally, I figure if I can smell someone smoking as I pass them on the street, even with a KN95 mask on, it's probably a good idea to wear a mask all the time.

In Massachusetts, it's very common although not universal. (And many, like myself, tend to pull up a gaiter when I get near, especially mask-wearing, other people.)

I see plenty of people wearing masks while hiking in Umstead State Park in Raleigh NC.