In my mind a 5-10 mph wind is a calm day, though I suppose I should have expressed myself more carefully. Regarding scent, as long as conditions are relatively calm, I usually don't concern myself much with it, other than trying to be downwind from my quarry if possible (often it isn't). When I first started chasing predators I was a fanatic about scent: I washed my clothes in scent free detergent, hung them outside to air for several days before a hunt, used cover scent, etc. But after trying it both ways, I couldn't tell that it made any difference. I know many seasoned varmint hunters are religious about it, though at least in north Arkansas it doesn't seem to matter.