I have a new definition for when it is too hot for fieldwork. Last week, the rig broke down, so the other geo and I had a free afternoon. We decided to do some recon in an area of cambrian arkose. The sandstone was somewhat ferruginized, the day was hot, the sky was clear, and there was no wind. About midafternoon, I tried to pick up a rock to get a better look at some stratigraphic features. I failed. I failed because the rock burned my hand. So, my new definition is this: It is too hot to do fieldwork when you can no longer handle the rocks with bare hands.