Climatology, Trends and Tendencies of Dew Point Data in New Jersey

Though only the 47th largest state by area in the United States, New Jersey's mid-latitude, coastal location allows for a wide range of dew point conditions. Despite these wide inter- and intra- seasonal variations, a seasonal and regional dew point climatology for the state has not, until now, been generated. Dew point data are analyzed for the period from 1981 to 2010 from five airport stations: Atlantic City, Millville, Newark, Teterboro, and Trenton. The geographic spread allows for New Jersey's coastal plain and piedmont areas to be examined.

Among the more interesting results, daily fluctuations of dew point at coastal plain stations (Atlantic City and Millville) are more strongly diurnal than at piedmont stations (Newark, Teterboro, and Trenton). April exhibits the highest average dew point depression, perhaps explained by diminished winter storms by spring, cool ocean temperatures, and the not yet prevalent southerly flow of abundant warm season moisture. An increase in dew point at all stations was noted over the 30-year study period. This is likely associated with a rise in atmospheric temperature and perhaps is also associated with variations in circulation and air mass frequencies.

Station relocations over the period of analysis may have also played a role in the dew point increase. However, the advent of ASOS instrumentation in the middle 1990s at these stations did not involve substantial relocation of instrumentation, with the possible exception of Newark's move to a grassier and slightly cooler location on airport grounds. It is also unlikely that the change in instrumentation played a major role in the increased dew points. Further investigation into the reasons behind temporal and spatial variations is planned.