Hot for Chicago Marathon

The forecast high temperature for Sunday's Chicago Marathon is 79 degrees. This may sound near-perfect to some, but it's quite hot for most runners. Because the body generates so much heat during vigorous exercise, research has shown that the ideal temperature for running outside is between 51 and 57 degrees. In fact, a few people in this U.S. Army study performed best with temperatures in the low-40s! A good rule of thumb when dressing for a good, hard run is to dress as if temperatures were 20 degrees warmer. So if it's a 50-degree day, dress as though it was 70.

Although temperatures will probably be near 60 when the gun goes off at the start of the race, most runners will finish with temperatures in the 70s. The sunshine will also make it feel hotter.