The December 15–17, 2020 nor'easter was a powerful nor'easter that hammered the Northeastern United States and produced widespread swaths of over 1 foot (12 in) of snow in much of the region from December 15–17, 2020, ending a 1,000+ day high-impact snowstorm drought in much of the Mid-Atlantic and coastal New England regions.

This low steadily deepened as it moved along and impacted the Mid-Atlantic coastline, prompting several winter-related advisories and warnings for much of the Northeast.

[4] The nor'easter originated from a disorganized winter storm in the Southern Plains of the United States, late on December 14.

The winter storm became more widespread the next day, as a low-pressure system developed, and it began to spread snowfall in Oklahoma and Kansas.

[4] On the next day, the system reached the Eastern United States and began spreading snow, ice, and rain across the region.

[5] Early on December 17, the system then moved off the coast and developed strong winds and heavier precipitation, while the snowfall spread northward.

[3] The nor'easter developed a secondary low to the east later that day and gradually began to weaken, as it began moving away from the Northeastern U.S.[8] A high-pressure system to the east of Atlantic Canada then steered the nor'easter away from the coast, after it passed south of New England, and the storm raced off eastward into the Atlantic.

[4] Early the next day, watches located from Virginia to Western New Jersey were updated to Winter Storm Warnings.

[13] 300 snow plows were deployed to apply salt to many major roads and bridges due to expected snowfall.

[17] NJ Transit suspended bus and train travel beginning at 6:30 p.m. EST as a result of the degrading conditions.

[20] Connecticut Governor Ned Lamont ordered all large trucks off the state's highways beginning at 9:00 PM EST on December 16.

[citation needed] Massachusetts Governor Charlie Baker urged residents in his state to stay at home during the nor'easter.

By 6:45 p.m. local time, Dominion Energy reported nearly 20,000 power outages, mainly across the Shenandoah Valley, western Piedmont.

The National Weather Service received a report of up to 0.6 in (1.5 cm) of freezing rain east of Galax and a half-inch in western Bedford County.

[27] Maryland State Police responded to 489 service calls on December 16 between 9 a.m. and 3 p.m. local time, including 161 crashes and 60 abandoned or disabled vehicles.

[29] On the morning of December 17, Spirit Airlines Flight 696 skidded off the taxiway after landing at Baltimore-Washington Thurgood Marshall Airport due to snow and ice accumulations.

[31] Strong gusty winds were reported as well, especially close to the Jersey Shore, where a peak gust of 62 mph (100 km/h) in Mantoloking was recorded late on December 16.

[33] In Philadelphia, Pennsylvania, the city recorded 6.3 inches (16 cm) of snow, the highest since 2018 and more than the entirety of the previous winter season.

[54] On December 17–18, as the nor'easter passed to the south of the province, winter weather caused various delays and closures, particularly in the Provincial capital, Halifax, where schools, government offices, recreational programs and public parks had delayed openings after 20 centimetres (7.9 in) of snow fell.