Long sleeve western shirt. Poly/cotton blend. Light color if possible. Done.
(This from Southern Arizona, where we know a thing or two about sunshine.)
Note that I don't actually do this most of the time. I just cover my head with a cap and go. But it's the simplest, most time-tested solution out here. And no goop to apply.
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A race bike in any era is a highly personal choice that at its "best" balances the requirements of fit, weight, handling, durability and cost tempered by the willingness to toss it and oneself down the pavement at considerable speed. ~Bandera