May 2026 – Continued Dry Across Delaware

May Temperatures

Preliminary data indicates that the statewide average temperature in May was 63.8^o F, which is 0.2^o F above the 1991-2020 average value of 63.6^o F (Figure 1).  May 2026 was the 37^th warmest May since observations began in 1895.  At the Wilmington, Dover, and Georgetown Airports (Figure 2a, 2b, 2c), the month began with cool temperatures featuring highs in the 60s and lows in the 40s at each station from the 1^st through the 3^rd.  While temperatures the rest of the month were mild, the most notable warmth occurred from May 18^th through the 20^th as all three stations reached daily high temperatures in the mid-to-upper 90s. 

May Precipitation

Delaware’s statewide precipitation for May 2026 averaged 2.25 inches, 1.33 inches below the 1991-2020 average of 3.58 inches (Figure 3).  May 2026 was the 34^th driest May since observations began in 1895. May was also the 10^th month in a row with at or below normal precipitation across Delaware.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperatures varied across the State, with most stations seeing positive or negative departures of no more than 1^o – 2^o F at most locations (Figure 4).  Precipitation was below normal across Kent and Sussex counties, while New Castle County experienced slightly positive precipitation departures (Figure 5).

National Anomalies

Temperatures were uniformly above normal across the western one-half of the United States.  They were near to below normal across most of the eastern portion of the country (Figure 6) except for portions of the Atlantic Coast including Delaware and New Jersey.  Precipitation was significantly above normal across the Gulf Coast and Ohio River Valley (Figure 7), and below normal across the Great Lakes and much of the Mid-Atlantic.  In general, the western one-half of the country saw varied precipitation and relatively small anomalies. 

Global Anomalies

May 2026 was the 2^nd warmest May on record for the globe since 1850.  Global temperatures were 1.93^o F above the 1901-2000 mean.  Of particular note this month were the warm temperatures across most of western North America, Europe and western Asia (Figure 8).

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