A 60° day in Denver is gorgeous. 50° in Denver is short sleeve weather if you are outdoors. The sun feels warmer than the humid weather in other states.
The meridian/ path of the sun changes, so it's arc is lower in the sky, during the winter, so the rays contact at a much steeper angle to our atmosphere... However, even though we are in a steeper angle, which causes our winter, the sun is physically closer to us, and because we have less atmosphere up here to filter the ultra violet, our UV index jumps in the winter.
So, the air is cold, but the sunlight is warm.
As far as jet coating goes;
It has more to do with what you'd like to see with under hood temps, than anything.
Any reflective coating will do it's job. There is a guy up in Golden that will do a set, inside and out, for around $100-150, depending on the tube length and overall square inch coverage. He does them inside and out, as well as piston tops, skirts and other parts, to help with oil and heat shedding.
I think you should do it, if for no other reason than to lower under hood temps, but I'd suggest having them done locally, because it's far less expensive and you don't have to ship.
Josh used VHT on the new header of his Honda CB650 and it chalked after about 2 months.
