Well, it's been as low as -2 round here, of late. I'm in the city centre as well.
If you step outside and end up jumping back in shrieking, "Feck me, it's a chilly one", then you may consider it to be officially cold.
I have.
Wire the thing into a 5-pin relay, along with all the fancy electro-crap, like heated grips.
Then build the solar panel into your leather saddlebags. That's what I've done and am chuffed to fuck, if I do say so meself!!
Or, secure it some-other-how.
Chain it on, lash it, tie it, bolt it..... Improvise, adapt, overcome!!!