Hi all, I'll be doing Mera Peak in October and at the moment I only have a synthetic belay jacket (Arcteryx Dually Belay) and not a down jacket. Will this suffice or do I really need a down jacket for the trip (presumably the MH Sub-Zero)?

12 months ago when I was there it was -30c, excluding wind chill, as I crawled out of my tent at ABC around 2:00am. Without a down jacket I am not too sure I'd be typing this response today.

However, as soon as the sun comes up circa 6:30am it warms up considerably and the jacket comes off. Unless of course the weather turns foul!

You will also find that nights & early mornings when you move up above 4000m get very very cold and the down jacket is just the best thing to keep you warm. I kept it stuffed at the bottom of my sleeping bag each night just to keep the toes warm.....

I'd suggest you would need one for sure, but I do believe you can hire them in Kat?????

You'll be fine in the Arcteryx jacket. It's a warm high quality mountaineering jacket. If it's down or not doesn't really matter in this case.
As Andrew says; you can rent down jackets in Kat, even in Namche, but I think you're probably better off in the jacket you have unless you find a really good deal. Most of those rental jackets I've seen are "well used".

mera is cold,bring a down jacket definitely!!

I agree.

My experience is that the line for a Down Jacket is around 5700M.

Mera is nearly 800 meters above that. You might not need it for summit day, but you'll certainly need it in the high camps at night.

There are differences between natural down and synthetic, but warmth isn't one of them.

Natural down has one disadvantage (loses all warmth when soaked) which probably isn't too relevant in the Himalaya, and one huge advantage (compresses very small when not in use; with related benefit of not weighing much).

If you know you won't get rained on, the compressibility of down is usually well worth paying extra for. But if you already own a jacket that's warm enough (Corax says it is), you will be fine if you stick with the one you've got.

nartreb wrote:There are differences between natural down and synthetic, but warmth isn't one of them.

Exactly my main point.

nartreb wrote:But if you already own a jacket that's warm enough (Corax says it is), you will be fine if you stick with the one you've got.

Under normal conditions the Ar'x jacket should fine.
What I don't really get when listening to discussions about warm clothing in the mountains is the fanaticism about down. Down is great, but there are other materials which suffice and also have advantages compared with down.
Another thing that makes me a bit curious (even mentioned in this thread) is that many climbers seems to have a set elevation limit when a certain type of clothing should be used. I've been above 7000 meters without down clothing, even summiting 6500 meter mountains in only a thermal underwear sweater without feeling cold, but I've also had hypothermia on very low peaks. It's all about the conditions. The jacket in question is definitely good enough for Mera Peak if the weather is normal, even on the rougher side, but no expedition clothing in the world will be enough if a violent fall storm hits.

Another important factor is what kind of a climber you are. Some are going on high frequency, with few or no stops. Others go slowly and take long breaks. It's huge difference. A friend of mine crossed the arctic, from Russia via the North Pole to Canada without any down clothing. He thought it was dead weight. He did bring a good down sleeping bag though.

I have not climbed that high before but why not take your belay jacket and add a light down sweater as a midlayer if you're cold? Something like the TNF Thunder or the Patagonia Down Sweater would layer as easily as fleece and might give you that extra bump. Then you'd have another arrow in the quiver for when the belay jacket is too much. I really don't think a MH Subzero would be any warmer than your Dually. It only has 600 fill down so it will be heavy and bulky. Something like the Absolute Zero or TNF Himalayan would probably be noticeably warmer but you'd need to spend a lot of money. I've been using a Patagonia DAS Parka (similar to yours) and friends who I have converted from down items such as the MH Subzero to synthetic belay jackets have all been pleased with change and do not complain about the warmth difference.

Thanks for all the comments guys - I was playing around with some down jackets in REI and I think my Dually should match some of them (apart from the much more expensive ones) so I'll probably stick with that...