October 2025 – Near Normal Temperatures with Below Normal Precipitation Across Delaware

October Temperatures

Preliminary data indicates that the statewide average temperature in October was 57.9^o F, which is 0.1^o F below the 1991-2020 mean value of 58.0^o F (Figure 1).  Although it was near normal for the last 30-year period (1991-2020), October 2025 still ranked in the top one-third of temperatures since observations began across Delaware in 1895. 

October Precipitation

Delaware’s statewide precipitation for October 2025 averaged 2.56 inches, 1.38 inches below the 1991-2020 mean of 3.94 inches (Figure 2).  October 2025 was tied with 1987 as the 48th driest October since records began in 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were mixed across the State (Figure 3), with many stations seeing negative anomalies in Kent and Sussex Counties, while much of New Castle County saw positive temperature departures.  Precipitation was below normal across almost the entire State (Figure 4) with most stations recording negative anomalies of between 0.5 and 1.5 inches.

National Anomalies

Temperatures were above normal across most of the central United States, while most of the Pacific Coast and much of the southeast Atlantic Coast saw slightly below or near normal temperatures (Figure 5).  Precipitation varied greatly across the country (Figure 6) with much of the eastern portions of the United States seeing negative precipitation anomalies except for portions of New England south through the Ohio Valley.  Most of the western United States recorded near or above normal precipitation for the month. The 500 hPa height pattern for October showed a weak jet stream ridge across the central portion of the country, contributing to the generally positive temperature anomalies across that region (Figure 7).

Global Anomalies

October 2025 ranked as the third warmest October on record for the globe since 1850.  Global temperatures were 2.21^o F (1.23^o C) above the 1901-2000 mean.  Particular warmth was found across central North America, and parts of Antarctica and the Arctic (Figure 8).

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