Preliminary data indicates that the statewide average temperature in July was 79.8o F, which is 2.4o F above the 1991-2020 mean value of 77.4o F (Figure 1). July 2023 was tied with July 2019 as the 5th warmest since observations began in 1895.
Delaware’s statewide precipitation for July 2023 averaged 6.75 inches, 2.33 inches above the 1991-2020 mean of 4.42 inches (Figure 2). This month’s statewide precipitation total was the 13th wettest since observations began in 1895.
Statewide Spatial Anomalies
Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were generally positive across the entire state (Figure 3). This month’s precipitation, like last month, was extremely variable across the State with values ranging from less than 4 inches at Jones Crossroads to over 13 inches at Bridgeville (Figure 4), a distance of approximately 15 miles. As is often the case, this variability was a result of the convective nature of rainfall during the summer months.
Temperatures were generally above normal along the Atlantic and Pacific coasts and the southwest United States (Figure 5), while much of the northern plains saw below normal temperatures (Figure 5). Precipitation departures were generally small across the entire country, except for portions of New England where significant above normal rainfall occurred (Figure 6). The 500 hPa height pattern for July shows a weak jet stream trough covering the upper Midwest and plains, contributing to the temperature anomalies found across that region and the precipitation anomalies in New England (Figure 7).