Hoping that someone with a read on current conditions might be able to help with this: my 18 year old will be backpacking in Yosemite next week on a high school trip. The details are not crystal clear about where they will be camping, but the best info is that they will be spending a night or two in Curry Village, then camping at higher elevation (possibly 9000 feet, not sure about that but want him to be prepared). The question is, should he bring a 20 degree down bag (Kelty Cosmic Down) or a 0 degree synthetic bag (EMS Boreal with Primaloft insulation)? He will be using an external frame backpack so bulk is not a problem, he could just lash the big synthetic bag to the pack. The synthetic bag weights at least a couple pounds more than the down bag though; he says he is not too concerned about weight, but I'm sure that he would appreciate carrying the lighter bag if he could get away with a 20 degree bag. He will also have a wool baselayer and insulated synthetic hooded jacket that he could wear while sleeping. Thanks in adance!

Please be assured that a 20 degree bag is more than adequate in Yosemite Valley or the Sierra Nevada backcountry this time of year. No need to lug around a huge 0 degree bag.

Yosemite Valley forecast for this weekend indicates a low of around 42F and @27F in the high country above 10,000 feet.

If, for some reason, he gets cold in the 20 degree bag, he can always add layers of clothing.

Not to worry mom!

Dad actually haha. Thanks for the information...you confirmed what I was thinking!

Oops, sorry Pop! I hope your son has a great time in Yosemite.

Send us a report after his adventure.

The 20° down bag did the trick, the lowest temps were in the mid 30's. He cowboy camped one night with no problems. Sounded like a great trip, not sure what trail they were on but he said they camped at Buena Vista Lake one night.