The news said something interesting and important this morning, and that if you're under this heatwave/dome and you have to spend ANY amount of time outside in it you need at least to spend DOUBLE the time inside and cooling down. If you were outside for one minute, you need to cool down and rest inside for at least two minutes. If you were outside for a half hour, you need to be inside resting and cooling down for a whole hour. If you were out there for two hours, you need four to recover, and so on.
Most importantly, stay hydrated. Even if all you drink is caffeinated soda, it's still better than not drinking anything at all. Pretty much anything other than alcohol and energy drinks like Monster and such are fair game for hydration (this coming multiple doctors I see who have said this to me, the caffeine in a can of coke isn't going to make you pee more fluid than you're taking in).
Stay safe, stay cool, stay hydrated, and wear sunblock when outside even if you think your skin is too dark to need it–Black people are more likely to die of skin cancer than white people because doctors are typically trained to identify it on pale skin. By the time it's big enough for doctors trained that way to take notice, it's often too late.