Cquartz DLUX, better than c4 in terms of durability. A bit more fiddly to apply.
With any semi-permanent coating the most important thing is the prep and ideally a heat gun to allow for faster curing unless working in a dry unit/garage.
In this weather none of the "gel" type products would really last all that well... best bet is using something regularly like AG Bumper care (I use this and it's fine to be honest), there are others from Chemical Guys, Poorboys, Meguiars, Auto Finesee etc....