A ground delay was in effect for Phoenix Sky Harbor International Airport as of 6 p.m. Friday, Feb. 9, delaying flights by about 43 minutes on average, according to the Federal Aviation Administration’s National Airspace System.

The ground delay was set to remain in effect until 10 p.m.

Unlike Thursday’s ground stop and ground delay, where severe weather delayed flights by 20 minutes on average and around an hour at most, Friday’s delay was due to inadequate staffing at the Phoenix air traffic control tower, according to the FAA.

A ground delay is when flights headed to an airport experiencing adverse conditions must delay their takeoffs. While the FAA can order a ground delay, it does not cancel flights.

As of 5:30 p.m. Friday, about 189 flights to and from Sky Harbor were delayed, though none were canceled, according to the flight tracking website FlightAware.

Michael Salerno is an award-winning journalist who’s covered travel and tourism since 2014. His work as The Arizona Republic’s consumer travel reporter aims to help readers navigate the stresses of traveling and get the best value for their money on their vacations. He can be reached at Michael.Salerno@gannett.com. Follow him on X, formerly Twitter: @salerno_phx.

This article originally appeared on Arizona Republic: Why are flights delayed at Phoenix Sky Harbor Airport? What to know