Chelsea Clinton Has Learned to Pace a Marathon

Chelsea Clinton ran her first Chicago Marathon on Sunday, finishing in 3:47:55 with Bill and Hillary Clinton waiting for her at the line, as we reported after the race, and her official splits show just how evenly she ran it. She went through halfway in 1:53:10 and covered the second half in 1:54:45, only 1:35 slower, while the temperature at Midway Airport climbed from 60 F toward 70 F. Four years ago in New York, the gap between her two halves was more than half an hour.

Clinton opened with her quickest 5K of the day, 25:51, and then ran every 5K after it between 26:46 and 27:41. Her slowest stretch came from 30K to 40K, including a couple of miles around the 21-mile mark at a little over 9:00 pace, and she found some speed again for the last 2.2K, which she ran at 8:08 per mile. From 35K to 40K she was 7.1 percent slower than over her first 5K. In a random sample of 2,042 finishers from our analysis of the full Chicago field, the median runner was 19.3 percent slower over that same 5K, and among the 10,035 people who finished between 3:30 and 4:00, the median second half took 7:36 longer than the first.

Her race looks a lot like Boston in April, where she ran her personal best of 3:40:52. She was 1:49:41 at halfway there and ran 1:51:11 for the second half, 1:30 slower, which works out to the same 1.4 percent she gave up in Chicago. Boston was a touch steadier through the middle, with every 5K up to 40K between 25:50 and 27:00, and her 10K from 30K to 40K was 1:10 slower than her first 10K. In Chicago that difference was 2:44, on a day she described to NBC Chicago as “a little hot.”

The most evenly paced race she has run is the New York City Marathon last November. Clinton went through halfway in 1:52:27 and ran the second half in 1:51:55, a negative split of 32 seconds, and all eight of her 5K splits fell within 58 seconds of each other, from 26:24 to 27:22. She ran the last 2.2K at just under 8:00 per mile and finished in 3:44:22, her fastest marathon until Boston.

At her first New York City Marathon, in 2021, she reached halfway in 1:50:27, within a minute of her Boston split five years later, and then slowed in every 5K after 20K, from 28:49 between 20K and 25K to 32:30 between 35K and 40K. Her second half took 2:08:42, more than 18 minutes longer than her first, and she finished in 3:59:09.

She went out even harder the next year, running 23:41 for the opening 5K, which at 7:37 per mile is the quickest 5K in any of the six marathons we have her splits for. The 2022 race was the warmest edition since New York switched to a November date in 1986, with the National Weather Service measuring 75 F and a dew point of about 63 F, Gizmodo reported. Clinton was at halfway in 1:53:12, almost exactly where she was in Chicago, but needed 2:27:22 for the second half, 34:10 more, and finished in 4:20:34. By the 35K to 40K stretch she was running close to 11:52 per mile, a long way off the pace she started with and the kind of slowdown most marathoners know too well.

By 2024 the gap was down to 5:11, with halves of 1:50:20 and 1:55:31 for a 3:45:51, and her pace only really began to slip after 30K. Of those six marathons, her four fastest are also her four most evenly paced, and the two where she faded hardest, New York in 2021 and 2022, are the only two she finished slower than 3:50.

Chelsea Clinton’s 2026 Chicago Marathon Splits

Chelsea Clinton’s Marathon Splits