I've had good results on fabric when reproofing with Scotchguard, but I don't know about leather gloves Stig? Be interested to hear how you go on though? (So is 50F your trigger point these days? - It's 10C for me which equates to 50F I see, so if that is your threshold for a comfortable ride, we're on the same page.)
My riding temps are
always the overnight temps.
Presently there is melting roadside snow still all about,
draining across the road and refreezing at night! wife heading to work this morning...
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I prefer at least 24 hrs of above freezing temps (see Thursday, here) to warm the road before I head out in the dark. Riding time air temps above freezing and warmed surface should prevent hidden ice from melted snow.
If roads very clear of ice events - I'll ride down into the 20's.
Crisp! - but a balaclava (or 2!), layers under wind-stop Oxford rain jacket, boots, rain pants over armored jeans, heated gauntlets and a scarf make for an OK ride out to see friends for coffee.
When in doubt - I'll drive it in my truck to reconnoiter the route.
The rain should also rinse the salt from the road. I'll still clean my scoot when I get home.
Stig