The 2007 Chicago Marathon was worse than expected. This would have been a phenomenal race, if not for the weather. Within the first 5K I seriously considered dropping out because it was just so hot. By 10K my legs were very sore (which is totally unusual for me.) I didn't have any problems getting water or Gatorade. I also wore a water belt which I wish I wouldn't have; my water became very warm quickly and my belt just ended up scraping my back because all of my clothes were so wet from having been dumping water on myself at every aid station.
After the half-way point, I noticed many runners passed out at the side, and others vomiting. I hit the wall many times and physically could not run at several different points, which has never happened to me in a marathon before.
With only 5K left, police were trying to create bottlenecks in order to stop us from running, and telling us that the race was canceled. I was in disbelief, and asked one officer what was going on. He said they had to call the race because there were too many people dropping like flies. He told me I would get a medal, but not an official time. I totally freaked out and ran the rest of the way in.
I was aiming to finish in 3:50 but BARELY scraped in at 4:33. Even at the finish area, which was a scene of chaos and confusion by this point, runners were still dropping and passing out from heat exhaustion. It was surreal.
I would like to point out that the spectators along the course were amazing. Many of them were spraying runners with their garden hose, or passing out ice, or even passing out water that they had bought with their own money. They were wonderful!
I plan to run Chicago next year; there is NO WAY the weather can be as hot 2 years in a row! (Knock on wood). I believe that this race will someday be my Boston Qualifier.
For my next marathon, I'm not going to wear a water belt. And, if I know it's going to be THAT HOT again on race day, I might choose not to run, like 10,000 runners in Chicago who didn't even show up to the start line.