you can't judge everyones result on the basis that the winner ran two minutes slower than his PB...the runners in 4th and 5th were just seconds off their PB's for the half-marathon. Kirui ran hard enough to win...which he still put 16 seconds on everyone in the feild. So to say Young's performance was worth a 1:03:30...and the others ran equivalent to 1:06:40 is obsurd.
As for the weather...the condition weren't ideal, but managable. The temps were 25 degrees centigrade(about 75-77 degrees fahrenheit) and 80% humidity. Ask Beardsly and Salazar about these conditions...they'd agree that the weather was fine.
Here's what the winner had to say about the weather...
Kirui was happy with his race: “The course was not very difficult,” he said afterwards, “I felt very good and the conditions were fine for me.
“I arrived yesterday convinced that I was going to run well as I have been one of the fastest in the world this year. I thought conditions here would not be so easy, which is why I only arrived yesterday, but they turned out fine.