Been there, done that, have the medal, have the T-shirt!
It was hot and it was humid. I also had a strange ache in both my knees and my ankles which towards the end made each step forward painful. I was doing OKish through 30km and a bit further, but after that the walks at the drinking stations became longer, and I walked the uphills towards the end. Finished in 4h 42min. The breakup into 20k/10k/5k times shows how I got more tired towards the end:
The first 20k took 2h1min and the second 2h 23min.
The first 10k took 59min, 2nd 62min, 3rd 67min, and 4th 76min.
5k times: 29min, 30min, 30min, 31min, 33min, 34min, 36min, 40min
Temp(left) and humidity(right) data from FMI for around 15-19 o'clock shows T=23-25 C and RH=70-80% at least.
In colder weather, with a bit more training, and without the knee-ache, the next goal must be to break 4h!
Update: the finishing times are distributed like this:
This histogram was produced by scraping the results website with one python script and the plotting the results with another.
Download the scripts hcm_scrape.tar (works on Ubuntu 10.04LTS) hcm_scrape.tar
A whole series of histograms are on picasa: http://picasaweb.google.com/anders.e.e.wallin/HCM2010Statistics#