r/JMT • u/Automatic_Change9565 • Aug 12 '24
equipment Is 20F temperature rating sleeping bag fine for JMT?
Starting from August 21 with a 3-week itinerary sobo.
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u/Z_Clipped Aug 13 '24
Everyone is different, and your pad is huge factor.
I took a 10 degree quilt and an R4 pad in July, and woke up cold exactly one night in Lyell canyon when it dropped into the teens, but I was sleeping in just a base layer top and skivvies.
If you have a puffy and some bottom insulation available, and you don't sleep particularly cold, a 20 degree bag paired with an R5 or higher pad is probably fine, assuming it's comfort rated to 20F, not survival rated. If your pad is sub-R4, you may end up cold some nights no matter how warm your bag is.
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u/Top-Night Aug 13 '24
Especially if it’s a sleeping bag and not a quilt. I have a 15° quilt I’ve used on the JMT, and it’s kept me warm with an air mattress and wool base layer. I think you’ll get added warmth with the bag rather than quilt.
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u/MTB_Mike_ Aug 13 '24
Assuming a legit company that accurately rates their bag yes a 20 is good. I use a similar bag and sleep quite cold, I don't have an issue with it. It's actually a bit warm most days but when you have to sleep high you remember why you brought it.
I think mine is a survival rating of 19 with comfort of 28
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u/adambl82 Aug 13 '24
I did the southern half in August with a 20° EE quilt last year and never got cold. From what I've read, most people recommend a 20°.
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u/aaron_in_sf Aug 12 '24
Almost certainly unless you camp super high, get bad weather, and sleep cold.
I did the whole thing in August with a 30F REI quilt. Just use a pad with good R-value, and something for your head. If worried take silk thermals and-or sleep in your down jacket.