Western Mountaineering SummerLite Sleeping Bag - Ultralight (0°C)

The Western Mountaineering SummerLite is an ultralight 0°C down sleeping bag that weighs from just 510g. It's for backpackers, thru-hikers and alpine climbers who count grams but still want a proper, fully featured bag.

Most bags this light cut corners. The SummerLite keeps a full-length #5 YKK zip, so you can vent on warm nights or open it out flat as a blanket, plus an insulated draft tube and continuous baffles that let you shift the 850+ fill power goose down over you on colder nights. The 12D ripstop nylon shell is light and the whole bag packs down to a 15 x 30cm stuff sack.

Choose it for summer and shoulder-season trips where speed and pack weight matter: fast-and-light missions, long trails and alpine bivvies in mild conditions.

Why you'll love it

• Rated to 0°C – reliable warmth for mild to cool nights
• From 510g – one of the lightest fully featured bags around
• 850+ fill power goose down – excellent compressibility and long-lasting loft
• Full-length #5 YKK zip – easy entry, full ventilation, opens out as a blanket
• Continuous baffles – move the down where you need it
• Packs to 15 x 30cm – disappears into a pack

Good to know

• Shell: 12D ripstop nylon
• Loft: 10cm (4")
• Total weight: 510g (165cm), 540g (180cm), 595g (200cm)
• Fill weight: 225g (165cm), 255g (180cm), 285g (200cm)
• Girth, shoulder/hip/foot: 150/130/97cm (165cm and 180cm), 152/132/97cm (200cm)
• Insulated draft tube along the zip
• Includes an ultralight stuff sack and a breathable mesh storage bag
• Made in the USA

Who it's for

Backpackers, thru-hikers and alpine climbers who want the lightest possible bag for summer and shoulder-season use. Suits beginners and seasoned lightweight travellers alike – just remember 0°C is its limit, so it's not a winter bag.