Baton Rouge earned the dubious distinction of being the wettest city in America for 2015. The bucket at Baton Rouge Metropolitan Airport measured 77.59 inches of rain in 2015, making it the highest National Weather Service ASOS site rain total for the top 100 most populated cities in the United States. 

Wettest Cities 2015

Top 100 (Population)

NWS ASOS Sites

*Through December 31

Baton Rouge led a trio of Gulf Coast cities to collect more than 70” of rain this year. Nearby Houston and New Orleans complete the top three while Atlanta and Dallas round-out the top five.

A major October rain event boosted Louisiana's Capital City to number one. 15 inches of rain fell over the final two weekends after the first 23 days of the month passed dry. Fed by the remnants of Hurricane Patricia, an active sub-tropical jet stream helped produce 8.6 inches of rain in Baton Rouge and New Orleans on October 25, very near single day rainfall records. One day earlier, 5.5 inches of rain fell in Houston. Just one weekend later, a Halloween severe weather event brought over 4 inches to Baton Rouge and more than 5 inches to Texas' largest city.

For Houston, 14 inches poured down through the month of May and bolstered Houston’s already bulging rain gauges. Just one month later, more than 5 inches could be attributed to Tropical Storm Bill.   

Significant rain in Florida clusters two other neighboring cities in the top ten as well. Miami and Tampa picked up over 9 inches during the month of August. Persistent, torrential summer storms created numerous drainage and street flooding issues for both.

It is worth noting that if you expand beyond the top 100 most populated cities, South Carolina’s “1,000 year rain event” of Early October would jettison Charleston into the top five. A remarkable single day total of more than 11 inches fell on October 3 thanks to a Hurricane Joaquin fed atmospheric river.

It may seem like an easy “cop-out” but El Niño can indeed be blamed for the big rain. If you have been following along with long-range forecasts, above average precipitation has been an expectation for the southern third of the country as per historical patterns in a typical El Niño event.

A stronger sub-tropical jet stream leads to shifting weather across the Southern United States. Without El Niño, the Northern Tier is frequented with cold air outbreaks and winter storms. However, a more dominant southern branch pushes all of this action north and brings significant rain storms and temperature variations farther south.

Effects of El Niño are much more significant in the cool season. October and November certainly saw a “wetter than average” pattern evidenced by precipitation totals on our list of rainiest cities. That was fall. Climate experts contend that December through February bring the most pronounced effects from El Niño. Baton Rouge, Houston, New Orleans—that could just mean: the wet get wetter.