Nearly the entire United States experienced warmer than normal conditions during May 2018, with some locations in the Midwest seeing temperatures 7°F to 10°F above normal (Figure 1). For Delaware, preliminary data indicates that the statewide average temperature in May was 67.8°F, which is 5.1°F above the 1981-2010 mean value of 62.7°F (Figure 2). This made May 2018 the fourth warmest on record since 1895. In addition, May 2018 was 16.7°F warmer than May, signaling an abrupt transition from the cold to warm season.
Delaware’s statewide precipitation for May 2018 of 7.18 inches was the fourth wettest since records began in 1895 (Figure 3). This May’s precipitation total was 3.32 inches above average for the month. The first five months of 2018 have been the 13th wettest since records began in 1895, with a total precipitation anomaly of nearly 5 inches for the year.
Statewide Spatial Averages
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were above normal across the entire State (Figure 4), with several stations recording anomalies of greater than 5o F. Precipitation anomalies were above normal across the entire State as well (Figure 5), with the largest anomalies found across southern Kent and Sussex Counties.