YANBU - I've done my share of working in kitchens, nursing homes, shops in ridiculous heat - and the uniform for all 3 included tights! Which the employers would not give an inch on - absolutely NO practical reason for wearing tights.
Dd is out of school now and luckily working for a sensible employer who has air con, let them wear cooler clothes and even provided cold drinks and ices!
The NUMEROUS threads on here though with mners reporting schools INSISTING on pupils wearing sweaters and Blazers (sometimes both!) in a heatwave is utterly ludicrous and potentially a health risk. Pupils with certain health conditions will have trouble regulating body heat. But for any child having to sit in stuffy classrooms in uniform suitable for winter and in some cases not even allowed to keep water handy is CRAZY! When I was at school we had summer uniforms - gingham dresses for the girls, shorts & polo shirts for boys. Absolutely no reason why smart shorts & polo shirts can't be uniform now (but then I think school uniforms are a ridiculous idea anyway).
Yes there should be a max, just as there's a min - I've worked in cold environments too, where the temp is below the legal min, they have legal exemptions and rules on how that's managed (appropriate clothing, frequent breaks etc) so no reason that can't be done for hot temps too.
Yaffingale (some username would love to know the origin) it IS becoming the norm due to climate change. I'm in the west of Scotland, I've only lived here 10 years but I've noticed warmer drier summers here year on year, while I didn't grow up here my family are from here & we visited regularly, usually in summer holidays - apart from '76 I don't remember weather like this 20/30/40 years ago. It rarely went above 25* iirc (I've tried googling for data but think I need to be a meteorologist or stats analyst to understand!).
Agree our buildings & town planning aren't suited to this weather - the glasgow science centre roof melted!