I will be trying to summit Rainier in the middle of June, and I'm trying to finish up my gear list. I'm asking for advice on layering.
For the upper body I'll bring:
-baselayer midweigth size S
-fleece 100wt size S
-windshirt hooded New Balance W size M – (fit is on the short side as with most women's garments). This is quite breathable and doesn't do much in rain. The hood is small, zips up to bellow the chin and will go under the helmet.
-down parka OR Maestro size S
I'm pretty sure a hardshell will be needed, which brings us to the first question: would you want the hardshell to layer under or over the down parka?
I already have these shells:
-SD Microlight W size M – doesn't fit over the Maestro
-SD Microlight size L
These 2 are PU coated polyester, don't breathe, promote condensation and are not seam sealed. The hoods zips up to about chin level.
-Wild Roses 8000m parka W size L
-Mammut Extreme size L – this one is really big on me
These 2 are old (~11 years) Gore-Tex XCR harshells, burly and heavy. They have pit zips, velcro cuffs, hoods that zip up (or velcro) to nose level and would offer the most wind protection.
These and the SD size L fit over the Maestro with room to spare.
For the lower body I'll wear:
-softshell pants OR Supercharger size S – nice and slim cut
I'm thinking I'll need another layer for the pants, but not sure what to choose from these:
-baselayer tights
-M65 army pant liners. I have 2 pairs: an equivalent to small but they are short and I'd have to take the boots off to put them on; an equivalent to medium, acceptable length and have buttons on the sides, so no need to take boots off, but heavier than the other pair (400g vs 250g).
-hardshell pants Mammut Extreme size M – these are Gore-Tex, old, heavy and really burly. They have strong reinforcements on the behind, knees and insides of the lower legs. They also have suspenders, side zips and side velcro, snow cuffs.
Sorry for the long post, thanks for reading!

