Warning: I opened our shed alone on a 95 degree Saturday and got heat sick in 20 minutes
Last Saturday I unlocked the shed at 2pm to sort donated tools and the heat index in Dallas hit 104. I skipped water and worked 20 minutes before I got dizzy and had to sit on the concrete floor with my head down. A guy pulling up to drop off a circular saw found me and got me into his truck with the AC blasting, then stayed until I could stand up. Now we keep a cooler by the door and nobody works alone between noon and 4. Anybody else have a hot weather rule that actually stuck?
That is a solid rule and your body made the call for you that day, but I would not put all the blame on working alone. Plenty of people drop in the heat because they skip water, not because nobody was standing next to them. The cooler by the door and the no-work window from noon to 4 will do way more than a buddy system, since a friend can just as easy forget to drink too.