I had been in hot climates up to 38 Celsius, and light colored clothing really helped to try keeping as cool as possible while cycling. I'm assuming that the white color of my helmet would have contributed to some heat reduction however small it may be, but I'll take whatever advantage I can get.

The problem now is how to deal with the money sunk into the Bell crash replacement program. Wait for a response or order from retailer now so I can get it as soon as possible. Or take it as a loss. Or possibly end up with two helmets.