I had a plan to hike Mt Willey on 01/09/2017. I wanted to hit the Tom/Field/Willey loop to bag all three 4000’ers but my hiking partner cancelled and I didn’t want to make that road trek back to the vehicle or be stuck hitching. I had been waiting to get my grubby little hands on the new Minus33 Thermerino Jacket and finally pulled the trigger on it. This was to be its maiden voyage. I’ll admit, I was apprehensive of taken an unknown/unproven (to me) product into Crawford Notch when it was -10* out. I own a heavier down jacket that I had been taking into the woods with me but was too excited for this jacket to leave it behind. I opted to throw an extra, “heavy” top in my pack just in case. I took the difficult Kenrod Trail up Mt Willey. I get pretty heated on the way up the trail and was able to make due with just my expedition weight base layer top, after quickly losing the ¼ zip Isolation top. The trek was difficult as expected and the ladders were completely covered in hard-pack snow. I broke my crampons on the way up the ladders and had to make due with just micro spikes. I wanted to play with the grey jays longer than I got to but it was just too darn cold out to hang out on top. 
At the top I changed out my base layer, thankfully no one was around to see that, and put on the ¼ zip Isolation, the heavy weight top and the jacket. I switched out the soaked Minus33 Cuff beanie for another dry one, played with the birds and headed down the trail. It was not long before I had to ditch a layer as I was too hot. I was surprised with this as I suffer from Raynaud’s Disease and lose circulation in the cold so it’s very important to keep my core warm. I continued down in the Isolation ¼ zip and the Thermerino Jacket. I ended up undoing the ¼ zip and opening the jacket up on the way down as it was so warm; I even had to carry the mittens. I often have to leave all the layers on when headed down the trail but I didn’t with this jacket. It’s lightweight, takes up about half the space as my down jacket and it’s warmer than my down jacket too. I’m happy to have it in my gear arsenal. 
Kenrod Trail off Mt Willey
At the top I changed out my base layer, thankfully no one was around to see that, and put on the ¼ zip Isolation, the heavy weight top and the jacket. I switched out the soaked Minus33 Cuff beanie for another dry one, played with the birds and headed down the trail. It was not long before I had to ditch a layer as I was too hot. I was surprised with this as I suffer from Raynaud’s Disease and lose circulation in the cold so it’s very important to keep my core warm. I continued down in the Isolation ¼ zip and the Thermerino Jacket. I ended up undoing the ¼ zip and opening the jacket up on the way down as it was so warm; I even had to carry the mittens. I often have to leave all the layers on when headed down the trail but I didn’t with this jacket. It’s lightweight, takes up about half the space as my down jacket and it’s warmer than my down jacket too. I’m happy to have it in my gear arsenal. Kenrod Trail off Mt Willey