On the average, the weather today is ideal for a marathon, usually in the mid fifties (around 12 for the Centigrade-speakers among you). This year, though, we have forecasts of temperatures in the upper 80's (around 30 C), which is way too hot for a 26-and-three-sixteenths-mile run. They're going to do it anyway. I hope the runners are sane enough to keep the pace down and not kill themselves. I fear that some idiots will see a chance to take advantage of a slow pack, and pour it on, and kill themselves.
I went out just at dawn when the temperature was a nice 61 or so. By the time I finished my seven miles (in 73:24), it was already starting to heat up. It feels muggy, too. Humidity is not good for runners.
An improvement of more than three minutes between runs is not the sort of thing I can expect in the middle of the season; I'd better enjoy the feeling now.