Sleeping bag ratings?

I'm a little confused with the temperature or comfort ratings that go along with sleeping bags. I know it may sound silly as I'll likely be in a tent with tarps around it in hopes to brake the wind as much as possible, but do these ratings account for wind chill or feels like factors?

When I see 3 season bags which season should I assume is not included? I assume winter, but I usually don't encounter temps below +10 F in the areas I'm likely to be staying.

The ratings will assume you are sheltered. I.e. not completely exposed. I don't find it makes a huge difference unless you are very exposed. putting tarps around your tent sounds like heavy overkill. get a better tent - or one suited for your conditions.



3 season normally means spring->fall - but look at the temp rating and base it on the conditions you will see depending where you are.

With most inexpensive sleeping bags, the ratings are pretty fictional--best to assume the real rating is 5-10*F above the advertised rating.

There are standards for sleeping bags sold in Europe, but even those are a bit iffy. Info on EN13537 sleeping bag standards. Note that there are several different rating standards. All the ratings assume that (1) you are "standard," whatever that is; (2) you are wearing a base layer top and bottom and a warm cap; (3) your sleeping pad has an R value of about 4. A few US companies have adopted the standard. A number of US companies don't use these ratings--testing does cost money and the ratings themselves have been questioned (supposedly, testing the same bag in different labs produced highly variable results).

Most of the expensive high quality down bags are pretty accurately rated: Western Mountaineering, Feathered Friends, Nunatak, Montbell. These companies all have a reputation to uphold.

Putting tarps around your tent will just result in a lot of condensation inside. A wet sleeping bag is a COLD sleeping bag!

Thanks for chiming in with the info I needed guys, I really do appreciate it.
Would anyone happen to know if the "Big Agnes Cabin Creek" ratings are accurate? I'm not married to the brand, but so far they offer the only double bag that looks appealing to the wife and I.

I hope someone more familiar with BA sleeping bags will pitch in. Most of their bags are based on no underside--just the sleeping pad in a pocket. Since I do lots of tossing and turning at night, and learned from childhood to take the sleeping bag with me when I turn over, I'd invariably end up with the pad on top! Your mileage, obviously, may vary!

My own experience with a 2-person sleeping bag is that they are quite drafty. Inevitably one of the partners will move so as to let cold air in. If it's a cold night, I'm much warmer in my own bag with both hood and the draft collar (around shoulders) drawn up really tight. IMHO, a better solution is for each of you to have your own sleeping bag but have compatible zippers (left zip for one and right zip for the other) so you can either zip them together or sleep separately, whichever you prefer. That also lets you each go alone without having to buy another bag!