Maryland Climate Bulletin (Summer 2025) from state climatologist

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We are pleased to share with you the Seasonal Maryland Climate Bulletin for summer 2025, which includes sea surface temperatures for the Chesapeake Bay and the state's coastal waters. 

 

You can access it from the following link:

 

https://mdsco.umd.edu/Bulletin/bulletin_mdsco_sum25.pdf

 

 

Points to highlight are:

 

1) Summer 2025 was warmer and drier than normal (i.e., 1991-2020 averages) in Maryland, with colder and drier-than-normal conditions in August, warmer and wetter-than-normal conditions in July, and warmer and drier-than-normal conditions in June.

 

2) The mean temperature was warmer than normal throughout the state, especially in Garrett County (2.0−2.8°F), Somerset and Worcester counties (1.0‒1.4°F), and Washington County (1.0°F); minimum temperatures were also warmer than normal everywhere in the state, with maximum values in the previously cited counties, but maximum temperatures were split between warmer (central Piedmont to the west) and colder (Eastern Shore) anomalies. Precipitation was below normal over almost the entire state, particularly in Frederick, Carroll, and Montgomery counties (3.2−4.0 inches deficit), which received 20 to 32% less precipitation than their climatological seasonal precipitation.

 

3) The partial water year 2025 (October 2024 − August 2025), except for northwestern Garrett County, was below normal everywhere else in the state, notably over Frederick, Carroll, and Montgomery counties (7−10 inches deficit) and parts of Harford, Kent, and Queen Anne’s counties (7−9 inches deficit). The region over Frederick received 18−27% less than its climatological water amount, while the region over Harford received 18% less.

 

4) Statewide, mean temperature showed that summer 2025 was the seventeenth warmest summer since 1895, while the maximum temperature indicated that this was the thirty-eighth warmest summer. On the other hand, the statewide minimum temperature revealed that this was the seventh warmest summer on record. Seventeen counties reached minimum temperatures within the ten warmest on record, and three of them within the five warmest; among these, Garrett County set a record, Somerset had its fourth warmest summer, and Worcester had its fifth warmest.

 

5) Statewide precipitation indicated that summer 2025 was the fiftieth driest summer on record. No counties were closer to any record, but Frederick had its twenty-eighth driest summer, while Washington got its thirty-sixth driest summer on record.

 

6) Sea surface temperatures in the Chesapeake Bay in summer 2025 were below their 2007-2020 mean over the majority of the Bay from the Upper Basin (1.2°F below) and the Middle Basin (0.6°F), where the anomalies largely occupied the main steam of the Bay and rivers on the Eastern Shore, to the Lower Basin where the extent of anomalies on the main steam diminished from north to south until they were confined to the waters along the Eastern Shore and rivers reaching the waters of the Tangier and Pocomoke Sounds (0.2‒0.4°F below). The waters off Worcester County’s Chincoteague Bay were also colder than the mean (0.2‒0.4°F below). On the other hand, warmer anomalies than the 2007-2020 mean appeared along the western shore waters from the Back and Patapsco Rivers (0.8-1.2°F above) to the southern Calvert County coast, where they expanded to reach the Taylor and Hoopers Islands (0.2−0.4°F above). The current all-basin mean temperature of 79.2°F was slightly below the 19-year mean of the dataset (79.4°F) and far from the coldest summer temperature of 77.5°F, set in 2014, within the 19-year record (2007−2025).

 

Please refer to the bulletin for more details, including the century-long trends and links of interest.

 

The bulletins are issued to monitor the state's recent surface conditions in a simple format, allowing Marylanders to better understand regional climate variations.

 

This bulletin is possible thanks to the hard work and data made available by our friends at NOAA National Centers for Environmental Information and the CoastWatch East Coast Node.

 

Please help disseminate this bulletin.

 

Thanks,

 

Alfredo

 

 

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............................................. 
Alfredo Ruiz-Barradas, PhD 

Associate Research Professor

Maryland State Climatologist
Department of Atmospheric and Oceanic Science 

3437 Atlantic Building, 4254 Stadium Dr.
University of Maryland 
College Park, MD 20742-2425, USA 
Email: [email protected]