O’Hare International Airport’s on-time performance came in dead last among 29 major U.S. airports in the month of June, new federal data released Thursday showed.

O’Hare dropped in both its rank among other airports and its on-time rate — and for both departures and arrivals — based on its performance in June 2014 versus June 2013.

Its on-time arrival rate slipped to a mere 57.94 percent in June of 2014. Its on-time departure rate was 64.99 percent.

The new data comes despite the debut last October of the first phase of the $8 billion O’Hare Modernization Program. The move switched O’Hare from using mostly diagonal, crisscrossing runways to mostly parallel ones aimed east and west of O’Hare.

Chicago residents and others east of O’Hare — even as far east as the 40th Ward — have been howling ever since and catapulting O’Hare noise complaints to record levels.

The new heavy reliance on east-west runways was supposed to reduce delays in all kinds of weather.

O’Hare did see far more rain than normal in June of 2014, at 7.81 inches, National Weather Service meteorologist Jamie Enderlen said. But it also saw unusually heavy rainfall in June of 2013, at 6.23 inches.

Some rainstorms impact travel more than others, Enderlen cautioned.

“It’s rain, wind direction, how tall the clouds are, thunder, lightning, fog — there’s many factors that play into arrival and departure rates,’’ Enderlen said. “And that’s just the weather side.’’

Amid the same June rains, performance for Chicago’s Midway Airport, on the other hand, showed mostly an uptick between June 2013 and June 2014.

Midway’s on-time departure ranking improved from 29th to 28th, while its on-time arrival ranking dipped from 19th to 22nd. However, the performance used as the basis for both those rankings improved, with Midway’s on-time departures rising to 60.40 percent and on-time arrivals rising to 71.35 percent.

After more than seven hours Thursday, Chicago Department of Aviation spokeswoman Karen Pride was unable to answer questions about the O’Hare developments.

Email rrossi@suntimes.com

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