What are the optimum scenting conditions? This morning was cool after some rain with a hint of mist and the faintest breeze. My dog seemed to be able to scent deer 200yards plus and the scent of their passing lingered a long time - or maybe the bucks had some aftershave to impress the girls!

Interesting question. I think it depends on what you are hunting and how. For example do you want a dog to follow tracks on the ground or scent the animal from a far without tracking it or find something sitting in a tree.

I think you basically have two factors to consider: warm air rises and cold air sinks. Which means that you have to consider the temp of the ground and the temp in the air. Furthermore it is important whether the temperature is rising or sinking and how humid the air is.

An example: hunting capercaillie with baying dog on sunny morning. Ground is cold, air is warming and rising lifting the scent upwards. Easy for dog to find tracks and follow them however when capercaillie is flushed and fly up in tree it might be difficult for the dog to find the bird in the tree as the scent is rising.

On the other hand the same situation in the evening. Ground is warm and the temperature in the air is sinking. Difficult to find tracks but easier to find bird in the tree as their scent is sinking with the cooling air.

You may notice with dogs that they sometimes don't follow the track exactly but short cut and go directly on the animal or how high they hold their nose, this will differ with different conditions (and different dog breeds of course).

also depending if your are on a stand, hide ( highseat) in the wood on, a hill wind can swirl. if you are a smoker you can see it.. on your place the wind could be coming from the left and after few meters he turn to total other direction. red deer got very very good smell and
sharp eyes

Olaf