I believe this is global warming, becoming real...
I live at 6600 ft. altitude, have no air conditioning, but practice intense management of my house and barn environment. Thankfully, this is an area of generally low humidity(I can NOT tolerate high humidity, so simply couldn't exist anywhere it is both humid AND gets hot!-nor where it routinely goes well over 100 daily, no matter WHAT kind of heat it is-like Phoenix!!)-and it nearly always cools off nicely at night here-so I use fans to move that air into the house at night, then shut it up tight early in the AM-drapes closed, open doors as little as possible, don't even bring my truck back into the garage if I've been out and the engine is hot(during the day; wait to bring it in until late at night)-my house and garage are well-insulated, which means they 'hold' the cool air very well, thankfully!
At the barn(75'X 36",insulated metal)-my stall doors to the outside face east, are shaded by the barn in the PM, so I shut my horses out until about 10 AM, then open the lower doors so they can be 'in or out',and unless it is raining/threatening rain, shut them out again(into their roomy runs)around 4 or so, when they have the shade of the building; if the weather isn't bad, they stay outside at night, at this time of year(on occasion, I end up out there in the middle of the night, letting them in, when a storm sneaks up!!)I keep water buckets both inside AND outside of their stalls, so I don't have to move them back and forth-the outside ones get warm in the sun by @ noon, but are later shaded by the barn and cool back off, and the inside ones are always cool(I have automatic waterers in the barn, but quit using them a couple of years ago...I don't like not being able to SEE whether/how much water each horse is drinking, believe that is a dangerous drawback of auto. waterers.)I have enough faucets/hoses that I only have to carry buckets to refill waters to two of the Minis at the barn-and then, not very far. The other minis are in a BIG semi-round corral with a 36' x 16' run-in shed, south-facing, so they have 'daylong' shade-and a water trough with faucet right there. My 'big' mare has a 125' x 25' corral, with a nice big shade tree just outside the west side,put there specifically so she would have shade when really needed-when the weather turns bad, I can let her into a connecting alley I constructed with portable panels, to a 12' square run in shed with its own 50' run. There is a faucet at one end; I run a long hose out to her water barrels in her big pen(which is actually one end of my arena, which I partitioned off with panels.) She has plenty of 'moving around' room, and I don't have to clean up after her so much! It all works pretty well, just takes time to manage it all.
Margo