What are some good ways to avoid condensation without adding much weight?

its tough in the PNW.  Physics are free and light, but they are tricky.

You need enough heat build up to move the dew point away from your body/ bag.  The more ventilation, the harder it is to control the dew point.  Conversely, not enough ventilation and you get condensation from your breath and body trapped and it will stick to the inside of the shelter.

In the PNW you have a lot of moisture in the air in winter. (essentially we sleep IN a cloud)  If you have too much ventilation, the cloud settles on your bag shell.  You need to build up heat enough to move the condensation away from your bag and have it condense on the shelter wall, or (the outside) of your bivy sack.  ITS GONNA GO SOMEWHERE-  your bag is the worst place.

If a single wall tent is used you have to seal it up to keep the heat in, and you will get too much moisture to manage and itll make puddles.  A double wall tent gives you a buffer of warm air (trapped between the inner and fly) to try to have the moisture collect there.  you will be trying to make the dew point happen on the outside of the tent body through the balance of body heat/ ventilation/ relative humidity.

A bivy sack is prolly your lightest option.  it gives you a little layer that is water resistant, but breathable enough to not trap moisture.  I suppose the hotter you sleep, the more breathable you can have (?)  Its the body heat/ ventilation/ relative humidity thing again, just closer to your body.  Too breathable, you lose heat and the dew point happens on you.  Not breathable enough, and it traps your body’s moisture in the bag. (your bivy did this)  …cheap bivy. I love SOL but this is a very finicky thing, condensation.  Their materials arent up to snuff for a big task like PNW moisture management.

Bigger tarp- OBV the rain wont be such a prob, but the puddles will seek yo ass out!!  just ask the PNWGGG attendees.

Thanks for the advice.  Is the SOL bivy isn’t a good option, could you recommend one that is?  Would you recommend going just bivy then, instead of bivy and tarp?  The few times I woke up with a completely dry sleeping bag were when I didn’t use a bivy or tent at all because there was no chance of rain.  And it seems like if I need to seal the tent up, I’ll probably need to get a bigger tarp, as sealing a 5’x9′ leads to the sleeping bag and my head touching the tarp and getting wet :)

Oh to just bivy!  But no, the cold rain would cool down the bivy shell and just move the dew point closer to your body (IN your sleeping bag).

Im not a tarp/ bivy guy (well twice) due to wife and dog so i cant say for sure which one is best, but last week by chance i saw an mld superlight under a monk style tarp and it was dry after windy rain. I was baffled, but i did not get in the bag, so it may have been kinda damp. but the shell was dry. Sorry to go right to a effin ‘arm-and-a-leg’ piece. Theres prolly some that be fine. I bet OR makes a good one. They are good at bivys and based in seattle

yeah, raised edges results in rain and dirt and stuff blowing in

better to have tarp big enough so the edges can go all the way down to the ground

I use bivy which helps.  About half the time when it’s not raining  I sleep without tarp and bivy works pretty good there too

To avoid condensation, I’ve found a A-frame pitch with the sides staked to the ground to be ideal.  I’m currently doing this with a MLD grace solo but an 8×11 would give you more room to move fore and aft if the wind were to blow rain into the front or back.

Another option that I’ve invested into lately is hammocking.  I’ve used on two separate trips this month where we had precipitation, once at our GGG when it rained non stop for 24 hours.  I experienced zero condensation, even when I pitched the doors shut on the tarp (wind would shift multiple times every hour).

At the GGG, a few people woke up to indoor/outdoor swimming pools.  With a hammock, this obviously isn’t an issue and a few people remarked that I had the ideal system for those conditions.