Bend in on the east(dry) side of the Cascade Mtns. which block a lot of the rain the west side gets It does snow here and get cold in the winters though
I live around 4300 Ft elevation due to living south of Bend a little ways, Bend is right at 3300 Ft in the old downtown portion of town.
We get more snow and colder temps(-25F) along with a lot more big pine trees and critters like Deer, Geese, Raccoons, Mice and other animals due to the elevation
I'm going to put the stock Wix replacement air filter back in and see what the fuel mileage does for the rest of this year, winter
What I saw may have been abnormal due to something I didn't catch like the brand of fuel and location I bought it in
Oregon has more than one diesel blend is what I'm being told
I don't drive as fast in the winters as I do the rest of the year due to ice and snow on the roads around here so that may have some effect on the mileage also