By Lee Davidson, Salt Lake Tribune -- Salt Lake City International Airport again achieved the best on-time performance for both departures and arrivals among the nation’s 29 major airports last year.

It has been flying atop such ratings for years — including finishing best in the nation for on-time arrivals in seven of the past 10 years, and for departures in six of the last 10.

Data released by the U.S. Bureau of Transportation Statistics show that in 2013, 85.04 percent of arrivals at the airport were on time as were 86.69 percent of departures — both best in the nation.

Finishing second to Salt Lake for arrivals was Phoenix at 83.79 percent, followed by Seattle at 83.41 percent and Minneapolis-St. Paul at 83.18 percent.

In departures, Portland finished second at 86.16 percent, followed by Seattle at 85.59 percent and Minneapolis-St. Paul at 83.95 percent.

Chicago Midway had the nation’s worst performance for departures, with only 66.6 percent on time — followed by Chicago O’Hare at 70.37 percent, Denver at 72.51 percent and Newark Liberty at 72.65 percent.

Newark had the nation’s worst arrival performance, with 70.36 percent of flights on time. Following it were New York LaGuardia at 72.17 percent, San Francisco at 72.66 percent and Chicago O’Hare at 73.52 percent.

Utah’s top-in-the-nation performance last year was merely sort of average for it — essentially matching its 10-year averages. Over the past decade, Utah’s average ranking was 1.6 in the nation for departures and 1.8 for arrivals.

Airport spokeswoman Barbara Gann said the rankings are a mixture of good luck and hard work. Weather, efficiency by airlines and everyone cooperating to coordinate efforts all played a role.

"Typically the No. 1 factor contributing to on-time performance is weather. And we’ve been extraordinarily lucky this winter with very little impact to our operations — especially in comparison to the rest of the country," which has had a tough year for weather-caused delays and cancellations, Gann said.