Delaware Climate Warm and Dry in May 2013

Above normal temperatures and below normal rainfall characterized Delaware’s Climate in May 2013.

Figure 1. Delaware statewide May temperature (°F) 1895-2013.

Figure 2. Delaware statewide May precipitation (inches) 1895-2013.

May Temperatures

Preliminary data indicates that the statewide average temperature in May was 64.3° F. This is 1.3° F above the 1981-2010 normal of 63.0° F (Figure 1) and the 5th straight May with above normal temperatures.

May Precipitation

Delaware’s statewide precipitation for May 2013 averaged 2.56”, which is 1.44” below the 1981-2010 mean of 4.0” (Figure 2). The below average precipitation during May was the 4th May in a row with below normal precipitation.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) shows that the average May station temperature anomalies across Delaware varied significantly with the only coherent area of temperature anomalies found along the Atlantic coast, where temperatures were significantly below normal (Figure 3).

Average maximum temperatures were below normal for much of the State except for southern Kent and northern New Castle counties. Average minimum temperatures across the State were above normal in most locations (Figures 4 and 5).

All stations in the DEOS network recorded below normal precipitation values for May 2013, except for two stations in the northeastern portion of Chester County, PA (Figure 6).

Figure 3. May 2013 average temperature departures from the 1981-2010 mean based upon DEOS station data.

Figure 4. May 2013 maximum temperature departures from the 1981-2010 mean based upon DEOS station data

Figure 5. May 2013 minimum temperature departures from the 1981-2010 mean based upon DEOS station data.

Figure 6. May 2013 precipitation departures from the 1981-2010 mean based upon DEOS station data