https://kufiya.org/
There's an auto-queue and at the time of writing this there's like 3600 people in it (and an estimated like hour wait), so no guarantee of anything being in stock by the time you read this; but I figured I'd post this in case anyone was waiting on them to restock. 
It's a light fabric, it's not terrible to wear in heat, imo.
Maybe if you get a solid black one that'd be different I guess?