variable visibility

variable visibility

[′ver·ē·ə·bəl ‚viz·ə′bil·əd·ē] (meteorology) After United States weather observing practice, a condition in which the prevailing visibility fluctuates rapidly while the observation is being made; the average of the observed values is used as the reported visibility, and it is reported only for visibilities of less than 3 miles (4.8 kilometers).