March 2023 – Warm with Much Below Normal Precipitation Across Delaware

March Temperatures

Preliminary data indicates that the statewide average temperature in March was 45.8^o F, which is 1.6^o F above the 1991-2020 mean value of 44.2^o F (Figure 1).  March 2023 was the 30th warmest since observations began in 1895.

March Precipitation

Delaware’s statewide precipitation for March 2023 averaged 1.82 inches, 2.30 inches below the 1991-2020 mean (Figure 2).  This month’s precipitation was the 11^th driest since 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly positive across the entire state (Figure 3) with the largest positive departures found in New Castle County.  Precipitation anomalies were consistently negative across the entire state, with most stations seeing rainfall more than two inches below normal for the month (Figure 4).   

National Anomalies

Temperatures were much below normal across the western one-half of the United States, with some negative departures reaching nearly 15^o F across the Dakotas (Figure 5).  The Gulf coast states generally saw above normal temperatures during the month (Figure 5).  Precipitation departures were mixed across the country, with the largest positive precipitation anomalies found across California (Figure 6). The 500 hPa height pattern for March shows an extensive jet stream trough over the western two-thirds of the United States contributing to the temperature anomalies across that region (Figure 7).

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