Marathon day weather: What will the temperature be?

The tens of thousands of runners who toe the line at the Bank of America Chicago Marathon this year on Sunday, October 9 will have lifelong memories of amazing fans, an expertly run event and a beautiful course. And there’s one memory in particular that will be burned in their memories forever (so to speak): The temperature on that fall day.

In 2008 runners endured hot temps and the year before that, 2007 was downright sweltering. In 2009, runners bundled up for a chilly 35-degree day. In other words: There’s NFW to know what hand they’ll be dealt. “The one thing you will constantly hear runners and running experts say is that weather is always going to be something you can’t predict,” race director Carey Pinkowski told us back in 2009, when we asked about moving the race to end of October to raise the liklihood of cooler (happier) running temps. “Chicago has become accustomed to looking forward to the marathon on this weekend, and at this time there are no plans to change the date of the race.” Changing the race date also would open a Pandora’s box of logistical problems, he says. “Given the size of the race and the fact that it brings so many people to Chicago, the race date needs to be secured on city calendars much earlier than a year in advance.”

On the upside, the 7:30am start time that was instituted back in 2009 (changed from the long-standing 8am kick-off) should help mitigate hot temps should runners draw an Indian Summer kind of day. No matter what day of the year Chicago’s race falls on, it’s tough to beat our flat, fast hometown course.

The big race's date changes from year to year, of course, so when predicting this year's race-day weather, we researched not past race days, but rather the temperature history of October 9th each year. Here's what we found:

2010
Temperature at 8am: 59º
Temperature at Noon: 77º

2009
Temperature at 8am: 50º
Temperature at Noon: 50º

2008
Temperature at 8am: 51.1º
Temperature at Noon: 66º

2007
Temperature at 8am: 57º
Temperature at Noon: 71.1º

2006
Temperature at 8am: 54º
Temperature at Noon: 69.1º

2005
Temperature at 8am: 52º
Temperature at Noon: 57º

2004
Temperature at 8am: 54º
Temperature at Noon: 64º