Average speeds on hilly terrain. Riding bagged-out touring or gravel bike. Studded tires when appropriate. I try to keep efforts below the sweat threshold in temps less than 45°F or so (Typically December through March). I sweat like crazy in the humid summer months, and that's fine with me.

Winter with snow & ice: 11-14 mph
Other seasons: 15-17 mph.
1-2 times/year on bag-free road bike: +/-18mph