It’s hot out there in Boston today – hot the way it gets in Arkansas or Georgia, but not too often up here. I, of course, will be hanging out in air-conditioned labs and offices, with no need to stick my head outside, but even so, this would not be a good day to run a small water-sensitive reaction. And I’ve done lab work under conditions that were a lot more coupled to the weather than this. My post-doc lab in Germany was under the “open the windows if you’re hot” system, like many German buildings, and the breeze would redistribute photocopies of JACS papers off my desk and send them towards the hall. Darmstadt never got to the high 90s Fahrenheit while I was there, fortunately (I heard plenty of complaints about the heat at much lower levels, but then I used to complain about how chilly it could get in July). You did have the humidity to worry about, though, both for sensitive reagents and for things like water dripping down the sides of condensers, etc. (The traditional remedy for that is to tie a paper-towel bandana around the bottom of the thing like a sweatband).
I did, though, experience real heat in the lab a few times in Arkansas. The old chemistry building had had its windows bricked up years before, which meant that if the AC faltered or failed, it got pretty toasty pretty fast on the upper floors. The first summer that I did undergrad research, it failed a couple of times and we (enthusiastic scientists all) kept trying to do lab work as the plastic caps popped off the old Mallinckrodt ether cans. (Slicing the metal alloy off of those to open them for the first time is a bygone experience, for sure). We eventually had to flee to the relatively balmy Arkansas summer outside – at least there was the chance of a breeze out there. I’ve spoken over the years with colleagues from India, though, about their experiences in university labs where if you needed to use diethyl ether, you pretty much had to do it in the middle of the night or wait until the rainy season. So I’m glad to have only worked under those conditions briefly!
The usual way that people measure those conditions is by what solvents are liquids or solids (or trying to become gases!) t-Butanol is a marker for a warm lab; it freezes at about 25.5 C (78 F). Diethyl ether boils at 34.6 C just over 94 F, so if that’s actually starting to go, you’re in a mighty hot room. You don’t hear as much about cold labs, but DMSO freezes at 19C (66F), and I’ve certainly worked in labs where it had solidified. (Sometimes you see labs where the AC is cranked so hard in the summer that the DMSO freezes up, which is impressive). Acetic acid is the next common thing that would go on you; that one freezes at 16.6 C, about 62 F, and I don’t think I’ve ever seen it as a solid on an open shelf, which is good.
Comments are welcome about memorable experiences at both ends of the scale!