Appropriate Sleeping Bag for March through July?

[Turkey Sandwich]

I'm planning on starting a thru hike in the last week of February or the first week of March. I don't want to have to buy two sleeping bags for the two sides of the temperature scale. I already have a sleeping bag liner and I'm generally a pretty warm sleeper. I'll probably also have plenty of clothes to bundle up in. What temperature rating should I opt for if I want it to be enough to handle the late winter/early spring in Georgia and not be too uncomfortable warm as the nice weather moves north? I was thinking 30 degrees. Should I go less? More?

[Luddite]

I would say you'd need at least a 20 degree with your liner. You could always sew a Ray Jardine quilt for the warmer months of the year if you don't feel like buying another sleeping bag. I think they're pretty cheap and you'd be able to save some weight.

[Praha4]

you may need something warmer than 30 degrees if you start in early March. I started April 19th this year, and used a Marmot Hydrogen (30 degree) bag, it was fine, coldest nights were in last week of April, there was snow at Silers Bald and Wayah Bald at night.... it started warming up pretty fast after May 1st, never got below freezing in the Smokies first week of May, but thats not to say it couldnt do it next year in May.

[Llama Legs]

I've accumulated (bought, found, gifts) enough different sleeping bags to experiment in all seasons over many years.

My recommendation for you would be to buy a killer lightweight down bag in the one-pound range (I have a WM Highlite 35 Degree) AND a cheap semi-rectangular synthetic bag, 1.5 to 2 pounds (45 to 55 degree, bike touring, etc). That gives you 3 great options. Nested, they'll get you down to 15-20 degrees. The down bag will do great in the mid range temps (most of your hiking). And when it gets too hot for down, you can just use the synthetic bag.

You'd either carry both or swap them (by seasons) over the hike. This is not unlike the current USGI system that weighs much more !

[The Solemates]

you need more than a 30 deg bag for a feb/march start! I wouldnt even consider taking a 20-deg bag, especially if you are starting in the last week in february.

We started our hike in february and had nights below 0 Fahrenheit. I took a 5 deg bag and my wife took a 0 deg bag. I would recommend something along those lines for a late feb/early march start. then, i would switch to a warmer bag after mt rogers.

i think with this starting point, it is going to require two bags.