Originally Posted by
showlow
I live in AZ. I went out riding during the heat wave the other week. Looked down at my computer and it said 119 at 1:19pm. The next week I did 70 miles in over 100 degrees with a lot of dirt roads and singletrack. So the answer to your question is 'depends'. I tend to tolerate heat well. I sweat a lot and it's dry here. If you're not sure how you'll do then go slow, be careful, and drink lots. Know the signs of heat stress.
Curious if you feel like the temp reading on your Wahoo is accurate. Mine always seems to read high.
I think the answer to the original question is I know it when I feel it. When the humidity is so high that sweat just pours out of my helmet, it's too hot. When I stop sweating even though I'm drinking as much as I can, it's too hot.