What does everybody do for sleeping systems.  When we did the trail we slept under the stars all but two or three nights (and only in an attempt to stop the bugs).  We had a plastic ground cloth large enough for all three of us and are 3/4 sleeping pads. 

We did the trail in June and it was pretty comfortable at night with a real light sleeping bag.  I thought maybe some spring hikers might add input on the temp. ratings on the bags they used?  I would really like to cut some serious ounces in the sleeping bag department.  So if you have any recommendations on models please let me know. 

Funny you should post this -- I had some birthday money saved up, so I just pulled the trigger on an ultralight sleeping bag.

It's a Mont-Bell UL Alpine Down Hugger #3 (how's that for a name?) and it's rated to 30 degrees F. It weighs just north of 1 pound and it's stuffed with 800-fill down. It compresses down to the size of, like, a cantaloupe (for lack of anything better I can think of).

And apparently it flies diagonally through the air, as shown above. I tested it out during Sukkot, which, admittedly, had some fairly warm nights, but with lows of something like 55 degrees F, I had to leave the bag unzipped because I got too hot. I feel good about the purchase because I think it'll do great on the INT, especially in mild weather.

That said, this is kind of an expensive bag, and you don't need something exactly like this to hike the INT. I carried a heavier bag on our INT hike and it did just fine; this one, though, will save me about 2 pounds. That means I can load up with booze and cigarettes! (Just kidding)

Yeah, that's a great question. Now that it's getting cool and windy here, I'll have to test it. My suspicion is that it will not do very well in the wind. The fabric is very light. I might have to use a tent in early spring/late fall. But I'll test it and let everyone know how it does.

Im gona be bringing my kifaru Regulator slick bag. I've got the 40 degree one weighing in at .69kg compressed

 Acorn:

Regarding your suggesting to do with closed-cell foam pad as opposed to inflatable, you should know that you can stick with the same Therm-a-rest brand and also get a closed-cell pad in America that will likely be better and cheaper than most of the items you are going to find in an Israeli camping store.  I own a Ridge Rest, but their Z-Lite line is also popular.  Both of those models come in different sizes, including 3/4 length models if you are really trying to go ultralight.

Hey, Ashen!

I'll offer my own answers; I'm sure Yankale will be happy to speak for himself :) My numbers will correspond with yours.

1) I asked myself the same question prior to our 2008 hike through the southern Negev, and then on our first night in Mitzpe Ramon, the temperature got down to about 35 degrees. I was really glad I had the bag I had. Some of our other guys got pretty cold. Also, that 30F bag was lighter than most 55F bags, and to purchase a 55F bag that used similar materials, I probably would have paid twice as much money. I was fine with getting the deal and then hiking with what I bought.

In short, if you pack only in accordance with the conditions you expect to face, you'll have a hard time when conditions aren't what you expected. And in my ultralight endeavors, I've actually found myself in the unenviable position of having to bum gear from other people, because all the improvising in the world couldn't make up for my equipment shortfalls. In environments like those you'll find along the INT, the stakes are even higher, and in the event of a shortfall, there might not be anyone around to help.

2) I've actually done a lot of experimenting with ultralight hiking/backpacking techniques, and I've found that they're quite oversimplified and overhyped. Let me take a wild guess and say you're reading Ray Jardine's Beyond Backpacking. That's a great book; I learned a lot from it and I have it on my shelf. But I think a lot of his ideas really only work in ideal conditions. The intelligently-pitched-tarp-blocking-the-wind thing is a good example.

In the desert, the wind really picks up after sundown -- I imagine because of sudden heat losses taking place at different speeds on different surfaces, creating areas of differing pressure. Whatever causes it, it can be quite dramatic, and you often go to sleep in beautiful weather, with cloudless skies -- and with fast, fast wind blasting you with sand and grit. Most campsites in the southern Negev are out in the open, so finding a nice natural shelter is not an option. And no matter how intelligently you pitch your tarp, you're not going to find a way to keep the air from moving. It swirls around, creates vortices, etc. A bivy might work, but a bivy plus a really light sleeping bag is much heavier than just a sleeping bag that may be a little overstuffed in order to ensure that it can keep you warm all by itself. And have you ever tried sleeping inside a couple of garbage bags taped together? Sometimes in cold weather I put a garbage bag around the foot of my sleeping bag, and while it seals heat in, it also seals in moisture, and it can get pretty gross.

Another thing to note is that when wind is causing heat loss, it only takes a small amount of air movement to make a huge difference. I'll quote that other doyen of backpacking, Colin Fletcher, here: "Wind drastically increases chilling effect -- and in theory two-thirds of the maximum increase occurs when the wind is blowing at only 2 mph" (The Complete Walker IV, p. 747). That means that unless you can really batten down the hatches (read: full tent, zipped up, so as to negate the effects of the strong desert winds), a warm sleeping bag, or a windproof one, is something to consider.

3) Wearing everything you brought with you is also something that can work well under certain conditions, and rarely in the real world. It's true, you can put on all of your clothes at night before you go to bed. But again, the desert poses a problem: you've been hiking all day and sweating constantly, and even though the sweat dries quickly, thereby keeping you cool, it's still there long enough to allow dust to stick to any moist place on your clothing. I still have a shirt from my 2006 hike that started out white, and is brown to this day. Every time you sit down, and your back, wet with sweat from your hipbelt and pack, touches dust or dirt, it sticks. You get the picture. Me, I'm not climbing into my sleeping bag with all that crap all over me.

Sure, I could wash my clothes every day, but no matter what, some of my clothes will be pretty nasty, and moreover, I don't really want to use precious water to wash clothes when I could be drinking it. If you were to wash clothes every day, you'd have to carry extra water every day, and that water weight would far outweigh the extra 8 oz. of down fill that would allow me to sleep only in my spare clothes/less nasty undergarments, feel a lot more comfortable, and prevent my sleeping bag from getting all nasty inside.

4) I do like the quilt idea; it's always made sense to me. I've only tried it in the sense that I've unzipped my sleeping bag all the way and just used it as a blanket while lying on my sleeping pad. Jardine recommends attaching it to the pad, but I don't think that would help me overcome my comfort issues; I hate just laying there on a foam pad. Call it habit, but I like sleeping on something that feels like a blanket, and for that the sleeping bag works well. But people without these issues might be served very well by a quilt.

I'm not trying to say that ultralight techniques don't work. All of them work in certain environments. Some of them work in all environments. And many of them work along the INT, but it also pays to be realistic. Don't stake your life on an only-partially-tested idea you've read in a book, and figure out what sacrifices you want to make in order to carry a super-lightweight pack. My packweight without water and food is usually between 15 and 20 pounds, and for me, that enables me to cover long distances without pain, and also makes me comfortable enough in camp to ensure that I get a good night's sleep.