What ya got and what’s the best?

I have a very light weight and well vented gore running one that is fantastic, can’t remember the name but have a browse.

I’ve got a Pace eVent 3×3. Not light, doesn’t pack down small, but weatherproof and very breathable. Easily fits into my Camelbak and suits decent long day rides as a waterproof & general windproof top.

For really light packable jackets you may need to look at some of the roadie type shell jackets, but these may be significantly less robust than a more MTB specific jacket.

Montane

+1 montane

Montane are the most packable I’ve found, and decently waterproof. The gillet in particular is so small and light there’s almost no point in taking it out of your bag.

I’m not really a fan of waterproofs though, except in really cold conditions they just boil me alive- I’ve got a very breathable Altura Attack jacket and I don’t think I’d ever wear it above zero degrees. For anything else, that’s what gilets are for.