Altitude Women's Down Sleeping Bag (25°F & 15°F)
BEST USE: Backpacking
PERFORMANCE: 2.5 Season
WEIGHT: 2lbs 6.1oz | 1080g
COMPRESSED VOLUME: 6.5 liters
Shipping & Returns
Our warehouse is actively shipping orders from 8am to 1pm MST Monday through Friday. Most orders ship in one business day, but the transit time can take up to 7 days, depending on your distance from Boulder, Colorado.
2nd Day and Next Day Air orders will ship same day if placed by 1pm MST, Monday-Friday (except holidays).
All orders are eligible for fast and easy returns within 60 days of purchase.
For more details, please check out our Help Center
The EN Rating scale is a scientific test to determine the warmth of a sleeping bag. The test produces a Lower rating (for male sleepers) and a Comfort rating (for female sleepers). Both are listed in the features table on the product page.
A unisex sleeping bag with a Lower limit of 14ºF means a man should be comfortable down to air temperatures of 14ºF. The same bag will also have a Comfort limit, in the realm of 27°F, so a woman would be comfortable down to an air temperature of 27ºF. These ratings require a sleeping mat with an R-Value appropriate for expected ground temperatures – without this, the sleeping bag itself is unlikely to keep the sleeper warm enough.
A variety of factors impact sleeping bag warmth - the above temperatures are merely guidelines, not guarantees. It’s important to think of a sleeping bag, an appropriately insulating sleeping pad and a liner as a sleep system. For example - if you plan on sleeping in nighttime air temperatures of 27ºF / -3°C, choose a bag with a gender-appropriate rating of 23°F / -5°C, plus a sleeping mat with an R-Value of 2.5 to 3, and consider a Reactor thermal liner.
Incredibly versatile, the Altitude women's down sleeping bag is snug and cozy when it's cold, and cool and ventilated when the weather warms. Shaped to match your natural sleeping position the Altitude is both comfortable and light enough to carry anywhere.
DESIGNED FOR WOMEN
Shaped for comfort
Narrower at the shoulders, wider between the hips and knees. Regardless of the position you sleep in (figure-four, on your side or on your stomach), this shape provides a significantly higher level of comfort by giving you the room to move without compressing the insulation.
Warmth from additional insulation
Additional insulation compared to unisex bags, positioned using different body mapping for thermal performance exactly where it is needed. The comfort and versatility-oriented Journey and Altitude sleeping bags have an additional Thermolite layer in the footbox to warm your feet fast. Temperatures for Women’s sleeping bags are shown using the gender appropriate Comfort rating.
Maximum comfort for a good night's rest
Construction details like snug-fitting hoods and oversized draft tubes keep you warm in cooler weather. As temperatures rise, the Free-Flow zipper system of the Journey, Venture and Altitude allow you to increase ventilation up to the point where the bag opens completely flat as a quilt. Super-soft fabrics are comfortable in any season.
You don’t have to narrow your options with a constrictive mummy bag – expand your horizons with a sleeping bag which fits the way you sleep.
The second highest-lofting down used in any of Sea to Summit’s sleeping bags. 750+ Fill Power indicates that one ounce (30g) of down will re-expand to over 750 cubic inches after compression. Higher loft means that less down can be used to achieve the same temperature rating – important for performance sleeping bags. The loft and down quality/composition are independently tested by the International Down and Feather Laboratory (IDFL) – a copy of the certification is supplied with every Sea to Summit sleeping bag. The down is responsibly sourced and RDS certified and treated with the environmentally-friendly Ultra-Dry Down™ treatment.
Ultra-Dry Down is a non-PFC treatment hydrophobic treatment applied to the down during down processing. It is not a coating (which would reduce the ability of the down to loft), it comprises of very small particles of a polymer that cause the down clusters / feathers to repel water. Hydrophobic down is not waterproof; but it absorbs less water than untreated down and dries much more quickly.
Ultra-Dry Down does not affect the loft or lifespan of the down, or its breathability. The treatment will last through at least 20 washings.
100% of the down used in our sleeping bags and quilts is independently certified to the Responsible Down Standard (RDS). The RDS certifies down against animal welfare requirements and tracks it from the source to the final product. The purchase of RDS certified products demonstrates demand for better animal welfare practices in the down and feather supply chain. Sea to Summit is certified to the RDS. To learn more about RDS visit https://textileexchange.org/standards/responsible-down/
Our Free-Flow triple-zip design ensures your sleeping bag retains maximum warmth and efficiency when needed and multiple ventilation options when it's not. The half-zip on the right side of the bag (left side on women's bags) provides freedom of movement for both arms, additional ventilation and allows the top third of the bag to be folded down as a mini quilt when the mercury climbs higher than expected.
Thermolite® HL-1 is part of the family of Thermolite® materials used in Sea to Summit sleeping bags, sleeping bag liners and sleeping mats. HL-1 high loft insulation is a fiberfill constructed with a unique 3D crimp of hollow-core and solid fibers, which provides excellent lightweight warmth with superior durability. The Thermolite insulation lofts up inside the Air Sprung Cells™ of our sleeping mats to prevent convective heat loss from your warm body to the cold ground.
Comes WithUltra-Sil™ compression bag and storage cell
InsulationUltra-Dry Down 750+ Loft
Shell FabricLightweight 20D Nylon Shell
Zip OptionsFree-Flow zipper system
|25°F Regular||25°F Long||15°F Regular||15°F Long|
Frequently Asked questions
Warm enough for shoulder seasons?
Yes. The high-lofting down, cozy hood and draft collar, and extra Thermolite® insulation in the foot box provide the warmth you need for cold weather. For cold weather, we recommend the Altitude 15°F paired with a greater than 3.5 R-Value sleeping mat like the Women's Comfort Light Insulated.
Really cool in summer temperatures?
Yes. The Free-flow zipper system means separate zippers on your left and right side and in the foot box. Open them for ventilation or turn the Altitude into a comforter.
Able to be zip together with another sleeping bag?
The main side zipper can be zipped to Sea to Summit Ascent, Trek or Traverse sleeping bags. The Altitude Regular and Long bags have the same side zipper length.