October Climate Bulletin

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"We are pleased to share the Maryland Climate Bulletin for October 2025, which includes sea surface temperatures for the Chesapeake Bay and the state's coastal waters. However, due to the federal government shutdown, the availability of our primary data source for the Bulletin has been affected, and consequently, the extent of the Bulletin has been impacted. The regular production of the Bulletin is only possible thanks to the hard work and data provided by our friends at NOAA National Centers for Environmental Information, the CoastWatch East Coast Node, the Institutions involved in the U.S. Drought Monitor, and the U.S. Geological Survey's Water Watch.

You can access the Bulletin from the following link:

https://mdsco.umd.edu/Bulletin/bulletin_mdsco_current.pdf

Points to highlight are:

1) Statewide averages indicate that October 2025 was slightly colder and drier than normal (i.e., 1991-2020 averages).

2) Regionally, the mean temperature was warmer than normal in some areas of the state, particularly over counties in the central Piedmont and the Eastern Shore. Colder-than-normal conditions appeared over parts of Garrett, Prince George's, and Charles counties.

3) Precipitation was below normal for most of the state, especially over portions of Saint Mary's, Charles, Calvert, Somerset, Dorchester, and Talbot counties, which received around 50% less precipitation than normal for the month. Above-normal precipitation was observed only over western Washington County, which received approximately 25% more precipitation than normal. The rest of the state, with below-normal precipitation, received around 25% less precipitation than normal.

 

4) Drought conditions deteriorated in October. The extent of the state affected by drought increased from 50% to 90%, with a rise in the areas having Abnormally Dry and Moderate Drought conditions. Moderate Drought conditions affected Garrett, Allegany, Washington, Frederick, and Montgomery counties, as well as western Carroll, Howard, Prince George's, Charles, and northeastern Cecil counties. The Severe Drought conditions in Garrett and Washington counties, and the Extreme Drought conditions in Garrett County that appeared in September, persisted into this month. Abnormally Dry conditions covered the rest of the counties in the Piedmont, and most of the counties on the Eastern Shore; Worcester and Queen Anne's counties, as well as parts of Wicomico and Kent counties, remained drought-free. The number of streams and rivers experiencing Below-normal and Much-below-normal streamflow increased this month.

5) The Chesapeake Bay sea surface temperatures (SST) in October 2025 were in the 63−70°F range. Regionally, they were below their 2007–2020 mean across much of the Bay, except in the waters north of Baltimore, extending into the Upper Bay, where warm anomalies exceeded 4°F. The coldest anomalies were found in the southeastern Lower Bay, in the Tangier Sound waters off Somerset, Wicomico, and Dorchester counties, as well as in the Chincoteague Bay (3–4°F below). The all-basin mean temperature of 66.3°F was still warmer than the coldest October in the 19-year dataset (2007-2025), which recorded a temperature of 62.2°F in 2002.

Please refer to the Bulletin for more details. The Maryland Climate Bulletin is issued monthly and presents the state's recent surface temperature and precipitation conditions in a clear and concise format, enabling Marylanders to better understand regional climate variations.

Please help disseminate this Bulletin.

Thanks,

Alfredo

 

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Alfredo Ruiz-Barradas, PhD 

Associate Research Professor

Maryland State Climatologist"