I was out the other night in the countryside, and I was looking out and could see all the nearby towns, but all the lights were flickering... any idea why?
Often caused by heat haze rising from the earth as it cools down at night. Much like the distrotion caused whilst looking at something above the flames of a bonfire.
The reverse can be true and an air frost containing falling ice crystals can do the same thing in cold weather, although cold air usually produces a more stable image than warm air.