Icon Definitions and Terminology
What is Barometric Pressure?
Barometric pressure can be described as the weight of the air at a specific location, measured in inches of Mercury (inHg) or hectopascals (hPa). The pressure at sea level is 29.92 inHg. Variations in barometric pressure are associated with changes in weather conditions. Falling pressure typically indicates increasing clouds, possibly bringing precipitation, while rising pressure means clearing skies with improving weather conditions.
Barometric Pressure History Chart
A Barometric Pressure History Chart is a graph, shown on many products, that tracks and displays the historical barometric pressure over a the selected time period. The chart curve represents the rate of change over this allotted time period. An example of a 12-hour barometric pressure history chart is pictured on the right.
Pressure or Weather Trend Arrow
Even small changes in barometric pressure can greatly impact the weather. The Weather Trend directional arrow icon, included on many products, will show one of the following three barometric pressure trend directions, indicating potential future weather conditions: