How wet can October get?

 

An October day in suburban Washington, D.C.

The nation’s capital just finished another rainy and gloomy weekend. However, unlike some past October’s, none of this weekend’s rainfall was particularly heavy. Here are some hazardous October rain events in the DMV (DC, Maryland and Virginia).

2021: The first three and a half weeks were very dry with a combined rainfall total of only 0.42”. However severe weather occurred on October 25, with a cold front following highs in the 80s. A coastal storm developed a few days later that brought additional heavy rain on October 29. Consequently, October 2021 finished as a wetter than average month.

October 25:  DCA – 1.55” / IAD – 2.42” / BWI – 1.96”
October 29:  DCA – 1.15” / IAD – 1.32” / BWI – 3.01”

2019: This October remains DC’s ninth wettest on record and wettest of the last 20 years with a monthly total of 6.66”. There were four days with at least an inch of rain in the nation’s capital. Although none of the totals were record-setting at National Airport, two of the four days produced rainfall records at Dulles Airport in northern Virginia. It was DC’s second wettest Halloween. These four days also accounted for more than 80% of the monthly rainfall totals at both National and Dulles Airports (5.97”).

October 16: DCA – 1.35” / IAD – 1.04” / BWI – 1.29”
October 20: DCA – 1.60” / IAD – 1.44” / BWI – 1.35”
October 27: DCA – 1.48” / IAD – 1.29” / BWI – 1.27”
October 31: DCA – 1.25” / IAD – 1.35” / BWI – 0.98”

2012: Hurricane Sandy was the strongest storm of the 2012 season and had disastrous impacts after its landfall as a “post-tropical” storm. It caused extensive coastal flooding and resulted in fatalities from the Caribbean to Canada. Sandy also set a number of rainfall and low pressure records. DC’s three area airports had daily rainfall records on October 29, including the wettest October days on record at Dulles and BWI Airports.

October 29: DCA – 3.85” / IAD – 4.26” / BWI – 5.51”
October 30: DCA – 0.84” / IAD – 1.00” / BWI – 0.92”

2005: Following DC’s driest September in 2005 with only 0.11”, the nation’s capital had its wettest October on record the following month with 9.41”. The same was true at Dulles Airport (0.15” in September 2005 to 9.22” in October 2005). That was largely due to two consecutive days with daily rainfall records at both National and Dulles Airports. The remnants of Tropical Storm Tammy combined with a slow moving cold front to bring widespread flooding to the Mid-Atlantic Region. 

October 7:  DCA – 3.63” / IAD – 3.50”  
October 8:  DCA – 3.67” / IAD – 2.79”

October’s summery start is about to change

 

An early October day in Washington, D.C.

October is the second of three months of meteorological fall and often features some of the finest weather of the year with mild days and cool, crisp nights. Average daily high/low temperatures in the nation’s capital range from 75°/58° on October 1 to 64°/46° on Halloween.  

DC’s warmest October temperature on record of 98° occurred on October 2, 2019. Eight of the last 10 Octobers have been warmer than average in Washington, D.C. Meanwhile, DC’s coolest October temperature of 26° has occurred twice, most recently on October 31, 1917. Temperatures at or below freezing in October are quite rare in the nation’s capital with none since October 20, 1992 (32°).

The nation’s capital averages 3.66” of October rainfall. However, eight of the last 10 October’s have been drier than average. Weakening tropical systems can sometimes impact the DMV (DC, Maryland and Virginia) in October with heavy rain and severe weather. Such was the case with the remnants of Hurricane Opal in 1995 and post-Tropical Storm Sandy in 2012.

Washingtonians can sometimes get an early taste of winter with light October snowfall. A trace of snow (too little to measure) does occasionally occur, with the most recent being in 2011. The earliest in the fall season the nation’s capital has experienced accumulating snowfall was on October 10, 1979, with 0.3” at National Airport.

NOAA’s Climate Prediction Center expects October 2026 to feature near average temperatures and rainfall in the nation’s capital. That would be in contrast to last October that was both cooler and drier than average.

How does DC’s September weather stand out?

 

A September day on the grounds of the National Cathedral

This month has become DC’s first wetter than average September since 2021. It will also finish more than a degree warmer than average. However, that obscures how changeable this month’s weather has been in the nation’s capital. 

Ten of the first 13 days of September were warmer than average in Washington, D.C. That includes highs in the 90s on the first four days of the month. September hadn’t had such a hot start to September since 2015. Although not quite record-setting, DC’s high of 98° on September 1 was DC’s hottest September temperature since it was 99° on September 5, 2023.

As hot as much of the first half of September was, the DMV (DC, Maryland and Virginia) saw a major shift in the weather pattern during the second half of the month. Washingtonians experienced eight consecutive cooler than average days through September 28. Measurable rainfall occurred on five of those eight days.

The nation’s capital will finish September 2026 with 4.26” of rain, compared to DC’s average of 3.93”. The wettest day was September 3 with 1.25” at National Airport. Following DC’s wetter than average August (4.27”), this month has given Washingtonians the first instance of consecutive rainier than average months since May and June of 2025.

The most memorable weather event this month was the early season Nor’easter that brought two days of measurable rainfall to the DMV on September 26-27. That also coincided with a stretch of cooler than average temperatures (eight days). Impacts in the DMV weren’t as significant as areas north and east of the nation’s capital, but were still significant. This was a long-lasting event that had far reaching impacts up and down the East Coast of the United States. Nor’easters are relatively rare events in September so it made headlines for a variety of reasons.