When it comes to flights departing on time, Miami International Airport’s performance declined late last year, according to recently released data from the department’s Bureau of Transportation Statistics.

By the numbers: 73.2% of domestic flights departed from MIA on time in December 2022, according to the U.S. Department of Transportation.

• That’s down from 78.1% in November 2022, a 4.9 percentage point drop.

The big picture: Nationally, just 69.1% of December’s flights departed on time, Axios’ Alex Fitzpatrick and Kavya Beheraj report.

• That figure is generally between 75%-80% in a typical month, albeit with predictable dips in the busy — and often meteorologically challenging — summer and winter travel seasons.

Between the lines: The real story in December was, of course, Southwest Airlines’ epic meltdown.

• Just 53.4% of Southwest flights departed MIA on time in December.
• Nationally, 57.3% of Southwest’s December flights departed on time, compared with 77.2% for Delta Air Lines, 72.5% for American Airlines and 70.7% for United Airlines.
• Southwest’s struggles dragged down the average for all carriers reporting data to BTS.

Yes, but: All indications so far suggest Southwest has recovered nicely since December, though BTS’ data reports lag by about three months.

• The airline has promised to update key systems that exacerbated December’s meltdown, as well as better communicate with passengers whose flights are delayed or canceled in the future.

What they’re saying: “We spend a lot of money on technology and recently put in a new state-of-the-art maintenance system, a new reservation system and a new human capital workday system,” Southwest CEO Bob Jordan told Axios’ Eleanor Hawkins.

What we’re watching: MIA saw a record-breaking number of passengers passing through the airport last year — 50.6 million.

• January and February also set all-time highs for those months, and now spring break travel is expected to set records.