Preliminary data indicates that the statewide average temperature in March was 48.0° F, which is 4.0° F above the 1981-2010 mean value of 44.0° F (Figure 1). March 2021 was the 12th warmest March since observations began in 1895.
Delaware’s statewide precipitation for March 2021 averaged 4.35 inches, 0.15 inches above the 1981-2010 mean (Figure 2). This placed this month’s precipitation total in the “normal” category. Only isolated areas of snow flurries and snow showers fell during March, with no snowfall accumulation recorded at the Wilmington/New Castle County Airport.
Statewide Spatial Anomalies
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly positive at all stations, with the largest positive anomalies toping 3.0° F at several stations across New Castle County (Figure 3). Precipitation was generally near normal throughout the State with the largest positive anomalies found across Kent County (Figure 4).
Temperatures were generally above normal across the eastern two-thirds of the United States, with the largest positive temperature anomalies (greater than 7° F) found across the Dakotas and Minnesota (Figure 5). Only the western United States saw below normal March temperatures. Precipitation anomalies varied greatly across the country with particularly heavy precipitation across the central United States. In general, both the Pacific and Atlantic Coasts saw below normal precipitation during the month (Figure 6). The 500 hPa height pattern for March shows a strong jet stream ridge across the eastern United States (Figure 7) associated with the high temperatures across the eastern portions of the country.