I can't really understand how you need to clear your throat though if you don't have phlegm; what exactly are you clearing? Is it just a dry cough response (cold air?), or are you actually spitting something up?
Phlegm production when doing cardio-type activities is pretty normal. Most cyclists and runners are hocking lugies everywhere. When I was running a lot, I used to look forward to coming back from a head cold because I knew I would spitting up a quart of grossness on the streets. Effective "snot rocket" management is typical, and most cycling gloves even have terry cloth patches on them which primarily get used for wiping the residue off from a misfired rocket.
A little gross, but it's true.
Some people can do things like reducing their dairy consumption to cut down on phlegm, but personally I don't care that much and have just gotten used to it.
On days where I figured it would be worse than normal (like coming back from a head cold) I would tuck a couple of folded paper towels into my waist band. Ten minutes into my run I'd blow all that crap out of me, clean up, and keep charging.