Therm-a-Rest Hyperion™ 32F/0C Sleeping Bag

The Hyperion 32F/0C is the summer-rated member of Therm-a-Rest's Hyperion mummy bag line, with a manufacturer comfort rating of 5 °C and a limit of 0 °C. It uses the same 900-fill hydrophobic goose down as the colder Hyperion models but far less of it — 220 g of fill inside a 460 g total weight, roughly 100 g lighter than the 20F/-6C version. Some features were trimmed to hit that weight: no draft tube and no pad-attachment loops, both present on the colder Hyperion, since a bag rated only to freezing tolerates a little heat loss at the zipper without hurting comfort. What stays is the half-length left-side zipper, a draft collar around the shoulders, and the same 10D nylon ripstop shell and liner with a DWR finish. Fill distribution favors the top and sides at roughly 70%, 30% on the back — the same logic as the rest of the range. Packed size shrinks to 14 x 15 cm. Built for warm three-season nights and summer alpine trips; anyone expecting near-freezing temperatures should look at the 20F/-6C instead.