Preliminary data indicates that the statewide average temperature in December was 40.6°F, which is 2.5o°F above the 1981-2010 mean value of 38.1°F (Figure 1). December 2018 was the 20th warmest December since records began in 1895.
Delaware’s statewide precipitation for December 2018 averaged 4.71 inches, 1.14 inches above the 1981-2010 mean (Figure 2). The December 2018 precipitation amount was within the top one-third of precipitation totals since 1895. Most precipitation fell across the State in the liquid form, with only a single snowfall event across the southern portions of the State on December 9th.
Statewide Spatial Averages
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were positive throughout the State (Figure 3), but varied in magnitude depending upon location. Precipitation amounts varied across the State, with the largest precipitation departures found across northern New Castle County and the smallest across Sussex County (Figure 4).