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Which Airports Have Fastest And Slowest Phone Download Speeds

United Airlines Ticketing DelayUnited Airlines Ticketing Delay
Long lines at the United Airlines ticket counter at Denver International Airport July 08, 2015. Andy Cross — Denver Post via Getty Images

Travelers trying to use the new Netflix download feature to grab a few episodes of “Stranger Things” on their phones before boarding a long flight will have a much easier time at Detroit’s airport than in New York or Los Angeles.

A report from Speedtest by Ookla, a consulting company that sells technology for testing broadband speeds, found wide variations in the average upload and download speeds–using either Wi-Fi or mobile cellular networks–at the 20 largest U.S. airports.

At the extreme, mobile network download speeds averaged almost 46 megabits per second at top-ranked Detroit Metropolitan Airport compared to just over 7 Mbps at last-placed LaGuardia Airport in New York. A wide speed gap can make a big difference in the real world. Downloading an episode of Netflix’s (NFLX) “Stranger Things,” a file of about 200 megabytes, would take just 36 seconds at 46 Mbps in Detroit, but 4 minutes at 7 Mbps at LaGuardia. For a 3 gigabyte high-definition movie file on the Apple (AAPL) iTunes store, the times would vary from 9 minutes to just over an hour.

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For Wi-Fi connections, the speed differences were even more extreme, with Denver Airport averaging downloads of almost 62 Mbps and Atlanta’s Hartsfield-Jackson Airport clocking in at less than 3 Mbps. That’s the difference between a barely-noticeable 27-second “Stranger Things” download and an excruciating nine-minute wait per episode.

The results are accumulated from millions of users of Speedtest’s mobile apps. The airport rankings were based on data collected in the fourth quarter of 2016. The company posted the full rankings and a variety of comparison tables on the web.

The report could be a good guide to help travelers choose whether to rely on their wireless carrier’s mobile network or use airport Wi-Fi. “Our data show that when it comes to airports, it’s impossible to guess which type of connection will be faster until you’ve actually arrived,” Ookla noted in the report.

For example, Laguardia came in last for mobile but ranked seventh out of 20 for Wi-Fi, with average download speeds approaching 20 Mbps. Overall, seven airports had faster Wi-Fi, three had relatively small differences, and 10 had faster mobile connections. The worst choice may be in Los Angeles where the famed LAX ranked 19th for mobile and only 12th for Wi-Fi.

Wi-Fi at LaGuardia and the Philadelphia airport was almost three times faster than mobile download speeds and almost twice as fast at the airports in Miami and Seattle.

On the other side, mobile downloads averaged seven times faster than Wi-Fi in San Francisco and Orlando, and four times faster in Las Vegas and Minneapolis-Saint Paul.

Ookla noted that airports that have made investments in improving Wi-Fi, like a $2.5 million program in Denver, showed improved results and called for more such spending. “If Idaho Falls Regional Airport offers 100 Mbps Wi-Fi (and our tests show on average, users were achieving speeds of over 200 Mbps) there’s a path to Wi-Fi success for every airport,” the report noted.