For Shade;
Swing Liteflex Lightweight Trekking Umbrella UPF 50+
To aid evaporative cooling;
Brunton Solar Panel and or Lithium battery pack + Coolermaster Excalibur fan (modified).
Thick woolen socks and or felt insoles to insulate the feet from ground heat.
Cotton String vest and of course lots of water.
Total weight for the brolly + 6W PV solar panel + fan is around 650gms, all of which can be rigged up using some paracord to the brolly as a sort of lightweight air conditioner when walking along as you constantly sip water. (you may get some strange looks though)
Even here in Scotland the sun may beat down mercilessly and raise temperatures above 80F on the odd occasion during the heat of the summer.