September 2018 was both remarkably wet and unusually warm — precipitation and average temperatures for the month ranked sixth and 10th, respectively, in Baltimore’s record books.
The month ended with 9.19 inches of rain at Baltimore-Washington International Thurgood Marshall Airport. That was the wettest September there since 2011, a month that included heavy rain from the remnants of Tropical Storm Lee.
Before that, September was wetter in Baltimore only twice during the 20th century, and twice in the late 1800s.
BWI’s average temperature during September, 73 degrees even, was the warmest for the month since 1970.
The average temperature was about 5 degrees warmer than normal, and closer to typical for August than for September. Temperatures have averaged above normal in all but three months so far this year.
All the September rainfall, on top of flooding rains in the spring and summer, has already ensured 2018 will be among Baltimore’s top 10 wettest years on record. There has been 54.45 inches of rain so far this year at BWI, about a foot more than average.