A lightweight breathable Primaloft midlayer
Lightweight insulated jackets are excellent for chilly days. They can provide better weather protection and more warmth than a heavier fleece. Mountain Hardwear’s Kor Strata Hooded Jacket is a good example. It only weighs 380 grams in the Large size but is as warm as the thickest fleece. It’s not designed as a garment to carry for wearing at rest stops or in camp. This is a jacket to wear while active. To that end it’s filled with Primaloft Gold Active and has a Pertex Quantum Air shell. Both materials are very breathable. They’re also environmentally friendly with Gold Active having a 55% recycled polyester content and Quantum Air a 59% recycled nylon one.
Designed for maximum breathability the Kor Strata isn’t fully windproof so in strong cold winds a shell is needed on top. It’s not waterproof either but does repel light rain and snow.
The jacket has a roomy hood that easily fits over a thick hat. The rim is elasticated and it’s not adjustable so it can blow off in strong winds, though in such conditions you’d probably be wearing a shell over it anyway. The three pockets are quite roomy too. The handwarmers can be used when wearing a hipbelt though the bottom of them is cut off. The chest pocket, annoyingly, isn’t quite big enough for a map. The cuffs are elasticated and there’s a drawcord at the hem.
Pertex Quantum Air is very soft and has a matt finish. It feels pleasant next to the skin and is very comfortable. The jacket stretches a little and has under arm gussets so when you raise your arms the sleeves don’t ride up. Mountain Hardwear says the Kor Strata has an ‘alpine fit’. I can wear the Large size comfortably over a lightweight fleece.
I think the Kor Strata Hooded Jacket is an excellent midlayer for cold weather. It’s very light for the warmth, very breathable, and very comfortable.