Load the editor , place a soldier 100 meters away , throw a smoke grenade in between and switch to thermal , notice how smoke covers heat imaging(Not just the soldier's but the general environment).
For the fog repeat the same with fog 100% this time , switch to thermals . Notice that in the fog the IR vision stops where natural eye vision also stops.
And for the environment temp change just place a unit , change the date to a summer month and watch it with thermals , then switch to a winter month and observe that thermal imaging (of the unit and the environment) is the same as before.