That's a really important fact! Many riders don't get this. Best to keep the sweat on the INSIDE. It's counterintuitive but it really works in very high heat. With just a bit of air flow, your sweat will help cool you as you ride ... even in 40C temps. Keep covered!

Also, even though you are sweating ... you are not losing as much water as you would riding in a T-Shirt. Also, good points about burning. Not just white people burn. Sun & Wind Burn will EXHAUST the rider. We see this all the time with the Harley crowd here. When it's hot they strip down to a bandana and tank tops, Beanie Nazi helmets. After two or three hours they end up in the emergency room with heat stroke.

I use a Camel Back drink system and in heat, drink constantly. a small sip every 3 minutes will keep you hydrated and safe. Try to keep moving and if you stop ... find shade.

Leather can be hot but remember ... leather is the "original" breathable material!

I've ridden with my leather pants through Mexico and Cent. America. I can ride up to about 85F to 90F without problem. Off the bike is when it gets hot. But non vented Cordura or other synthetic pants (Cold weather/Winter type) I sweat TWICE as much as Leather. I carry both ... and switch from Leather to Moto pants at around 85F to 90F. Nothing like Leather for protection.

All my Moto off road pants flow a lot of air ... so very comfortable in high heat not good if it cools off. I put Rain pants over when cold. Amazing.

Virtually ALL off road riding gear today is made in either China, Korea, Vietnam or Pakistan. Even Klim is made in China. With Chinese goods you can get Crap at closeout prices .. or pay more and get really well made gear.
You get what you pay for ... If BMW are making Cars and bikes there ... you know the quality is there ... if you're willing to pay.

In the old days lots of dirt bike gear was made in Finland. Like Sinsalo and many other top brands. No more. Those days are gone ... sadly.