No weather delays since 99. We were delayed one year due to a traffic snafu.
Here is the link to the historical temps
http://disboards.com/showthread.php?t=2353327
Of these the worst conditions were as follows
Wet
2002 - It rained - scratch that - it was a deluge. Sopping wet for me from about mile 7 on. As I recall it rained off and on for a good 20-30 minutes. Though I did dry the weather for the remainder was muggy. I did not know the parks actually puddle as badly as they do.
Hot
2007 marathon We started at 67F and near 100% humidity. It was near 80 when I finished just after noon It cost me an Ipod (never thought that pouring water over my head would kill it), and over 80 minutes added to my marathon time. I was fortunate as I slowed drastically to the 6+ marathon. I was moving at a sub 5 for about half the race. I saw the start of the great water bust of 07. They were beginning to fold up water table as I passed still well within a sub 6 run. The 16 minute folks were screwed.
Cold
2001 was the coldest start but the wind was calm. It is really a tie between 03 and 06. The wind was howling in 03. The temps do not do the bite of the wind justice. The front came in overnight as I recall and the winds just cut through you. I was fortunate as Mears Bus had a snafu at the resort I was staying at so I was sheltered from the wind until about 5:30. We arrived at the parking lot at 5:30 and had just enough time to drop baggage, potty and get in the corral. 06 was just cold. There was a wind. I did not pull my throw away shirt off at all during the half. During the full, folks backs were frosting over on the stretch from Epcot Dr to the MK Parking. I pulled my throw down shirt off at mile 10. I have my gloves and headband on in my AK photo. As I recall, I dropped my gloves and band at mile 17 where I saw my wife. I came back to the villa post marathon and took a hot bath just to warm.