More than 83% of U.S. flights departed on time in December 2023, per a new Axios analysis of the latest Transportation Department data.

Why it matters: It's a big upswing compared to December 2022, when Southwest Airlines' epic meltdown dragged the industrywide average down to about 70% for the month.

Zoom in: Florida's Destin-Fort Walton Beach Airport (89.5% on time), Salt Lake City International Airport (89.2%) and Hawai'i's Lihue Airport (88.8%) had the best on-time departure performance in December 2023 among airports serving more than 1 million passengers annually.

• Fort Lauderdale/Hollywood International Airport (67.2%), Baltimore/Washington International (69.5%) and Orlando International (76.1%) had the worst on-time performance — not counting Puerto Rico's Luis Muñoz Marín International, at 75.8%.

Between the lines: A variety of factors, from weather to issues at a particular airline, can affect any given airport's on-time performance.

• Denver International's numbers really tell that story. It posted an 81.1% on-time rate this past December, compared to 57.7% in December 2022.
• Denver is a major Southwest hub, and bad weather there helped spark the airline's infamous 2022 meltdown.

The bottom line: 83% is a pretty solid nationwide performance — especially during a month when winter storms can really disrupt the entire air travel system.