Greg M Says: "My sleeping bag is rated to 0 degrees, but it was only 30 and I froze, what gives?"

Well, Greg, in my experience it is usually best to assume that the person asking the question is an idiot, and work from there.  So, you froze because the bag was rated in degrees Celsius, and you were measuring in Fahrenheit.  See, a fahren's height is only 5/9ths as tall as a celsi, fahrens also have a baseline higher by about 32.  The math is complex but, this works out to be that you were actually 2 degrees below reported temperature (2 degrees Fahrenheit). 

However, if you are not an idiot, you deserve a longer answer.  First, it is important to understand how the ratings are achieved.  There are different organizations which provide guidelines for testing things.  Some of these are ASTM, ISO, and FEMA.  ASTM and ISO are industry standards, FEMA is a government standard and is much easier to get good marks using this benchmarking system, as long as the item is never required to actually be used, then the obvious flaws appear. 

The tests are performed in the following manner.  A bunch of people are placed in the sleeping bags and then put in a cold room (The actual number depends on which standard is being used.  If you try doing this at home 5 or more would be best to get a statistically relevant data set).  The temperature is gradually lowered until everyone dies.  From here statistics are run to determine the LT50 of the bag (Lethal Temperature 50, or the temperature at which half of the people die.  The LD50 for pharmaceuticals is calculated the same basic way.).  The ASTM and ISO standards require the company to report the temperature rating at 2 standard deviations above the LT50, which corrosponds to about a 3% death rate at that temperature.  Most of these people were anorexic, looked sickly and probably would have blown away in a stiff breeze if they had actually tried camping; so the actually user population is safe.  FEMA standards allow for the reporting of the real LT50 and actually allows for simulated testing done on paper, and even that is negotiable with proper campaign donations.

So Greg, go buy a new sleeping bag so you can then camp safely, as long as you use an RV.  One with a heater.