Above normal temperatures and heavy rainfall characterized Delaware’s Climate during summer 2013.
Preliminary data indicates that Delaware had its 4th summer in a row with above normal temperatures. The Statewide mean summer temperature of 76.0 °F was 1.1 °F above the 1981-2010 normal of 74.9°F. This summer’s warmer than normal conditions placed it as the 11th warmest summer since records began in 1895 (Figure 1).
Warm temperatures were accompanied by extremely wet conditions across the state during the summer season. The statewide mean precipitation of 21.41” was 8.96” above the 1981-2010 normal of 12.45”, and was the wettest summer since 21.8” of rain fell during the summer of 1989 (Figure 2), and the 5th wettest summer since records began in 1895.
Statewide Spatial Averages
Data from the Delaware Environmental Observing System (DEOS) show that mean summer temperatures across the state varied from generally warmer than normal conditions in northern New Castle, southern Kent and northern Sussex counties to below normal, especially along coastal regions (Figure 3). Mean summer maximum temperatures were generally below normal across the entire state (Figure 4), while mean summer minimum temperatures were above normal in most locations (Figure 5). The lower maximum temperatures and higher minimum temperatures are consistent with the heavy rainfall the state saw during the summer.
All stations in the DEOS network recorded above normal precipitation values during summer 2013. Precipitation anomalies reached greater than ten inches in portions of northern New Castle County and in eastern Sussex County. The driest areas of the state were found in southwestern Kent and northwestern Sussex Counties (Figure 6). Even in these locations, precipitation was above normal for the summer season.