Was riding around in the extreme heat today in Beijing (high of 37 deg C / 100 deg F), in direct sunlight, while wearing a 3/4 helmet, a mesh jacket and thick denim jeans. I had to pull over to cool off in the shade for a bit as I began to exhibit clear signs of heatstroke: dizziness, an elevated pulse and feeling faint. All despite keeping fairly well hydrated by drinking plenty from the bottle of water I had with me. Removed my jacket and thankfully managed to cool off just enough to be able to continue riding to my destination.

Which brings me to my question. Now that summer proper is here, what do you wear to i) stay safe and ii) keep cool while riding around in the extreme heat?

Note: some of you know I ride around on an electric scooter... be good if we can avoid turning this into a "why on earth do you need to wear all that gear on an electric scooter" discussion.