Winter 2023-2024 – Very Warm and Very Wet Across Delaware

Winter Temperatures

Preliminary data indicates that the statewide average temperature in Winter was 40.2^o F, which is 2.9°F above the 1991-2020 mean value of 37.3° F (Figure 1).  Winter’s temperature was the 9^th warmest since records began in 1895.   

Winter Precipitation

Delaware’s statewide precipitation for Winter 2023-2024 averaged 15.83 inches, 5.78 inches above the 1991-2020 mean of 10.05 inches (Figure 2).  Winter’s precipitation was the 3^rd wettest in the last 130 years.  In addition, Delaware saw four snowfall accumulations this year, with the largest accumulation of nearly six inches occurring on January 19^th.  

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were positive across the entire state (Figure 3) with some locations seeing positive anomalies of more than 5° F for the winter in northern New Castle County.  Precipitation anomalies were strongly positive across the entire state, with the largest departures of more than eight inches found in southern Kent and northern Sussex counties (Figure 4). 

National Anomalies

Temperatures were above normal across the entire country (Figure 5).  Positive anomalies of over 9^o F were found across the northern tier of the U.S. from North Dakota to Maine.  Positive precipitation departures were found along both the Pacific and Atlantic coasts (Figure 6) while below normal precipitation was scattered across other portions of the country.  The 500 hPa height pattern for Winter shows an anomalous jet stream ridge located over the northern U.S. and Canada, associated with the positive temperature anomalies found across these regions.

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