found a couple of interesting things about heat and humidity affect running.
One is based on adding the temperature and dewpoint together:
90-100 is probably ideal, anything below 130 is pretty much OK to go for a fast time (maybe 120 for longer distances, say HM or above)
Between 130-150 will see a gradual slowdown in pace
Above 150, forget pace altogether and just focus on finishing
Today's race conditions (as of 4 p.m., checking after my daughter and I got home):Temp - 92, dewpoint - 73 ..humidity above 50
I'm very frustrated to say, for the second year in a row: DNF.
Pre-race: I felt rested enough from the taper, and slept reasonably well last night. Woke up at 4:30 a.m. (for 7 a.m. start). I usually have some oatmeal at home before long workouts, but being on the road, I brought along a bagel and started eating that right away (nothing new on race day, right??). Also had a banana at 6 a.m. Got to transition by about 5:45 a.m. and picked out a good spot (lots of room in a very nice set-up). So not rushed. Got in a short swim to stretch out.
Swim: A two-loop course (exiting the water after the first loop so they can check numbers). Too warm for wetsuits, unfortunately. The water felt 'heavy' and I felt rather sluggish throughout the swim. But I stayed focused on technique throughout (good catch and pull; hip rotation; full breathing), kept very straight lines in the water, and had very little interference. Yet the swim was a minute slower (47 min) than last year.

They started us in two large groups, but again, that wasn't a hindrance. I was actually in about third place overall ...for the first thirty yards as a couple of us ran down the beach before cutting into the water.

Then the guys started to pass me by ...
T1: Under three minutes as I geared up for the bike while talking briefly with my daughter.
Bike: It started off OK. I was prepared to go a little slower due to conditions. But I did notice in the first few miles that (a) I had some labored breathing at spots, (b) I was dripping some sweat, and © my gut felt full and a bit off (most likely the bagel). All are rare so early in a ride. First hour on the bike was at a bit over 18 mph, which I would have been happy with. But I noticed that I had to go with a lighter gear than all my training to be comfortable. Also, I was just hitting some of the few serious hills on the course. Even before the far turnaround, I was getting to the point that I couldn't hold the big ring in front, and that has not happened at
all in training. That killed any efficient riding. By the return, I realized I had bonked. I couldn't hold strong gears, and couldn't put any strong push behind my pedaling. And still twenty some miles to go! Regarding hills: The fastest I've hit on a downslope on a Chicago trail was 26 mph. On this course, I was over 30 mph a few times, maxing out over 36 mph - not something I'm used to. So climbing those few hills was a foreign experience to my muscles. Very fun to hit that speed, though (with some bend in the road on that fastest hill). At the last water station, with me already struggling mightily, they hand me a Gatorade ...as I ride on and twist the top to drink, I find they forgot to remove the inner seal.

At around mile 41, a rider comes alongside me and says "hey, tri-man!" It was a guy I knew from about 25 years ago. We rode the last miles together and caught up on things.
T2: Because of the bonk, I decided to bag the run (like last year

). I know ya can't un-bonk. So to start a half-marathon in that condition would have accomplished little. I knew I'd have to report to you guys, which weighed on my mind. But I
hate doing that run/walk thing. And too, I'd put in 4:20 for the day ...struggling through another couple hours could have been risky.

I'll cheer on Wraith's first tri next week, then pick up my own sprint tri in two weeks. Maybe I need to stay with the shorter distances.
2Young -
so sorry to hear about your accident! That rightfully qualifies as a bad day. I do hope you don't have lingering issues from the crash.