I whistle whilst riding... It often times ends up being a song by Brit Brit.... Holllla!

As per riding wear, I have a fairly thin pair of Burton AG's, and for the most part, I just rock a thin pair of fleece pants under them. The AG's have vents on the outer and inner thigh which is KEY on warmer days.

come spring time, I tend to just rock a pair of shorts, or boxers under the AG's.

I also have a pair of thicker/more insulated pair of Quiksilvers that I use for the colder of colder days.
I find as long as my pants can block the wind, my legs generally stay fairly warm..
Only on a few occasions did I miscalculate and wear the thinner pants on a cold day. But not too too bad.