Short of actually knitting yourself a sweater out of bobcat fur, there's no better way to stay warm on summer nights than The North Face Lynx 40 Degree Synthetic Sleeping Bag. One of the lightest, most packable synthetic summer bags on the market, the Lynx is EN rated to keep you easily comfortable to 47 degrees, and won't have any issues if temps drop down into the 30s. How' The North Face's Heatseeker Pro insulation sandwiches super compressible synthetic between layers of rugged filament, providing serious levels of warmth and packability without adding extra weight. The mummy design is ultra efficient, too, cutting down on material while maintaining warmth, making the Lynx a top shelf summer backpacking bag. Of course, it'd all be for naught if your bag got wet, right' Not quite. Synthetic insulation stays warm even if it gets wet, so damp nights won't necessarily be sleepless ones. There's also a draft hood and collar to seal out cold air, a snug hood to trap heat around your head, and loops to keep your bag securely attached to your sleeping pad. Even the zippers are designed to be snag free, and have glow in the dark pulls for enhanced awesomeness.