The heat index and temperature can affect the UV Index, but not directly. Back to the Top Visibility Definition Visibility is the distance one can see at ground level. On clear days, visibility can stretch for dozens of miles. But haze, smog, fog and clouds all reduce visibility at ground level. Visibility is particularly important for pilots, drivers and boaters, because decreased visibility makes it more difficult to spot potential obstacles, giving the operator far less reaction time.
Visibility can tend to be low in the early morning hours, as morning fog is common in many areas.
Definition The perceptive difference between actual temperature and the way it feels when factoring in the wind speed . Wind reduces the amount of body heat retained, so the effects of outdoor temperatures on the body must factor in the current wind chill. The colder the temperature, the greater the impact of wind speed on the apparent temperature. For example, if it's 10 degrees and the wind speed is 20 mph, it will feel like it is 24 degrees below zero. The speed at which the wind is moving in relation to the ground.