@elilla Also, if you're unable to get shade when you're forced to be outside, you can make your own portable shade with a parasol or umbrella provided that it's not too windy.
Also important to monitor for early warning signs of overheating. If you're prone to any kind of weird mental health stuff (eg anxiety) and it suddenly turns up to 11 for no obvious reason? Get indoors and get cool. It hits everyone differently, but in biochemical terms, your body can't tell the difference between a high arousal state and overheating - so mental health stuff can be your earliest sign that you need to cool down ASAP.
(However, note also that with how overnight heat can affect sleep and the cumulative effects of heat stress, your mental health *will* take a hit, unfortunately. There's no getting out of that.)