Well, both are easy enough objectives. The rub is finding a bag that does both at the price you desire.

For your wildland firefighting gig I should think most any bag rated to the mid-30s or higher would be fine. I mean, for the most part, if there’s a forest fire going on you’re not really apt to be in the snow with 30-degree temps, no? With that in mind, REI’s Nooksack UL +35 ($159; rei.com) would be just about perfect. It’s fairly light (two pounds, five ounces), compacts well, and is insulated with PrimaLoft, which performs very well in damp weather (in case of thunderstorms and the like). It’s $159. And really, Marmot’s Pounder ($159; marmot.com) would do nicely as well even though it’s rated to 40 degrees. As its name implies, it weighs a mere pound. It also uses PrimaLoft insulation.

Making the leap from a hot summer in the West to winter in Alaska or the Tetons, working as a dog-sled guide, is a big one. You’re looking at temps of around 0 F and probably much lower. So your summer bag isn’t really going to cut it. At a minimum, I’d suggest something such as Mountain Hardwear’s Lamina -15 ($210; mountainhardwear.com), which uses a proprietary fill material to give you a fairly light (four pounds, 13 ounces) bag that can go below zero without sending your bank account into the same territory. But use it in the summer? No way. The North Face’s Tundra -20 ($239; thenorthface.com) is another good cold-weather bag. It employs well-regarded Polarguard Delta and has a water-resistant shell.

I really think you’re looking for two different bags here. You might shop around, try eBay or Craigslist, and see if you can find a deal somewhere.

You’ve seen our picks for 2007 Gear of the Year, and now the entire Outside Summer Buyer’s Guide is online. Check out this year’s more than 400 must-have gear items, including sleeping bags.