Yeah.. air temperature and atmospheric pressure affect how much fuel and air is delivered. (so does humidity.)
Fuel is not really sucked up through main jet, into the intake manifold and into the engine. It is pushed up by atmospheric pressure.. pushed by the weight of all the air above you.
Carburetors float bowls are vented to the atmosphere. When there is lower air pressure in the intake manifold (a "vacuum") than there is above the fuel surface in the float bowl, fuel is pushed up the jet. More atmospheric pressure means more fuel will be pushed through the jet. This means the mix gets richer with more atmospheric pressure.
Run the bike on top of a mountain where air is "thinner" and atmospheric pressure is lower than down at sea level. Less pressure is pushing on fuel in the bowl. This would make the mixture lean.
However, since the air is thinner on the mountain, there are less air molecules per cubic foot of air. This makes the mixture rich.
Air temperature also matters. Cold air is more dense than is hot air. Denser air means more air molecules per cubic foot and leans the mixture.. (more air, less fuel)
Humidity is water in the air. If a cubic foot of air contains lots of water there is less room for air. High humidity means less air which means a rich mixture.
All these opposing forces make it very difficult to accurately tune a bike.. Race tuners do it right at the track according to the immediate weather conditions, altitude, etc. They have special tools that simplify things a little.
Plug chops and accurate plug reading is about the best the average person can do.