Sea Level Pressure

The atmospheric pressure at mean sea level.

Sea-level pressure The atmospheric pressure at mean sea level, either directly measured or, most commonly, empirically determined from the observed station pressure.

The sea level pressure is the atmospheric pressure at sea level at a given location. When observed at a reporting station that is not at sea level (nearly all stations), it is a correction of the station pressure to sea level. This correction takes into account the standard variation of pressure with height and the influence of temperature variations with height on the pressure. The temperature used in the sea level correction is a twelve hour mean, eliminating diurnal effects. Once calculated, horizontal variations of sea level pressure may be compared for location of high and low pressure areas and fronts.