Originally Posted by AU338MAG
Originally Posted by traindriver
Originally Posted by AUwrestler
Originally Posted by kntree
Temp drop = thermals lowered
Temp rise = thermals raised

What, and how do, other variables affect thermal movement, i.e. hills, swamp, lowland, wind? Anybody have edumacated knowledge on this?


Other than the basics you stated, be mindful of steep inclines either from rocks or cedars. This can cause the air to swirl back on itself. Like an Eddie in a river. A light wind and thermals will work together. But heavy wind will push the thermal the direction of the wind. Don't get lazy and think that mornings = rising thermals. Really cold mornings with no wind will continue to sink. Humidity also makes air heavier. Use this cause bucks may be traveling on the bottom. I think the best thing to do is to keep a journal. Monitor temp and forcasted wind. Then write down actual scent direction at that stand and try to figure out why so you can learn more about all your other stands. Still learning myself, but I'm getting to where I like hunting mountains better than flat cause of thermals and hunting benches.


Increased humidity DECREASES air density, i.e. makes it lighter. Use a psychrometric table or air properties calculator. For example, where I hunt, elevation is 300' above sea level. For 32 F and 40% RH, air density is 0.07974 lb/cu ft. If RH increases to 80%, density is 0.07966 lb/cu ft. Molecular weight of water is roughly 18 g/mol regardless of liquid or gas phase. Air without water is roughly 29 g/mol. More humidity = more water = reduced density for the overall mixture.

Yes, it only feels heavier to us, but humid air is lighter. Long distance shooters know this.

Good to know. Thanks guys.

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