i met a guy who swears by cling film/Saran wrap *over* summer clothing for occasional high altitude or bad weather days, though he warned about it melting on various hot parts and was very careful to say you shouldn't wrap it too tight.
Technique he showed me (in the pub) was to sit on a chair then wrap thighs first, then very loosely over the knees, down to the ankles, tighter down there.
Then a run of sellotape up the front, over the sitting knee, up to mid-thigh, then another run either side of your shinbone.

He was adamant he wasn't taking the p1ss and claims that you can get both clingfilm and sellotape in most small towns as long as you ask around. Post offices or business offices can help you find sellotape, cafe's can help you find clingfilm (even if they don't use it themselves). He suggested carrying a picture of each on your phone to help language problems - fair enough.

I wasn't convinced he was sane until he produced a grainy pic on his fone at the top of Tizi-n-Tichka in an icy snowstorm next to a snowplow truck in the early 2000s. I was suitably impressed, recognizing exactly where he was.

Not being a biker myself* I'm unsure how practical, if at all, this clingfilm malarky would be, though in an emergency you'll try anything I guess.

This conversation then prompted one of his mates to say that he'd seen some locals riding with "cowboy chaps" made from heavy plastic bags and handstitched (knicker-) elastic bands in the Andes, to protect the front of the legs on the high passes. This sounded more sane than the clingfilm and a lot trendier.

* dedicated pister in Moroccan hire cars - Duster 2WD all the way nowadays