Preliminary data indicates that the statewide average temperature in June was 70.6° F, which is 2.0° F below the 1991-2020 mean value of 72.6° F (Figure 1). June 2023 was the second month in a row with below normal temperatures.
Delaware’s statewide precipitation for June 2023 averaged 3.31 inches, 0.78 inches below the 1991-2020 mean of 4.09 inches (Figure 2). This month’s statewide precipitation value fell within the “normal” range since observations began in 1895.
Statewide Spatial Anomalies
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly negative across the entire state (Figure 3) with many locations seeing negative anomalies of more than 3° F. This month’s precipitation was extremely variable across the State with values ranging from approximately 2 inches in Sussex County to nearly 12 inches at Prices Corner in Wilmington (Figure 4). This large variability was due to the convective nature of the month’s precipitation with several intense thunderstorms impacting isolated areas.
Temperatures were generally below normal across the eastern and southwestern United States (Figure 5), while much of the northern tier and Texas saw above normal temperatures (Figure 5). Precipitation departures were varied across the country, with the central one-third of the country seeing mainly below normal values (Figure 6). The 500 hPa height pattern for June shows a weak jet stream trough covering most of the eastern United States, contributing to the temperature anomalies found across that region (Figure 7).