Which sleeping bag for the Northern Sierra July-August?

Just got back from my own Sierra ramble (a story for another time)…I normally also use a 20 degree FF Hummingbird and love it as my main bag.  This trip I went with a 30 degree Zpacks quilt.  I carried no puffy (just relying on my Alpha and rain jacket combo if I needed it.  I never did.  I do use Goosefeet sleep booties as my feet get cold….and I do have a Nemo Extreme I use pretty much year round.   We all sleep differently for sure and I consider myself to be a cold sleeper.  I saved 11 oz with the quilt and I cold feel that on my back.  I think you are good for sure with your plan.  If you have a cold night, you can always put on that puffy.

I’ve been snowed on every month of the year in the high Sierra but, yeah, you’re likely going to be more comfortable in the 40F bag than the 20F and it sounds like you’ve got enough extra gear to be comfortable if it got down to freezing.

Remember you can swing night time lows 10-15F higher by not camping in the open (IR loses to deep space on clear nights) so get under some trees; not being on the valley floor but 20 feet higher to avoid night time inversion layers (created by that radiant cooling to space); and not camping right along water courses where cold (and humid) air can spill down from upper elevations.

Rain gear in California in the summer is for afternoon thundershowers.  If you’re trying / having to make miles and keep hiking, so be it, but another approach is to hole up in afternoon if the thunderheads start forming, not go over the pass just then, get in your tent, and wait 2 hours for it blow over and hike into the late afternoon / early evening instead.

Keep in mind that an EE 40° bag is comfort rated to 50°. Were it me, I’d grab an EE 30° or a Katabatic 40°. I’d rather be a little toasty than a little chilly.

In 25 years of Sierra trips I have never brought a quilt/bag rated warmer than 40°F comfort for June thru August. I typically camp between 11-12K’ in a good tent and know what I’m doing.

Leaving in a few days on a two week trip to the Goddard area and packing a 13 oz bag with 8 ounces of down

Last August, over 18 days between Tahoe and Tuolumne, the coldest night was 36 degrees at a little over 10k. Mostly mid 40’s. That forecast with the 90’s must be for a fairly low elevation. I just checked point forecasts for a couple spots in northern YNP, they showed highs in the mid 70’s at elevation around 7500 and 8500 for the next 7 days.

I would NEVER go into the Sierra without rain gear…. never!

I once start a week long backpack with an NOAA forecast of sunny and clear for a week…. day after we arrived up high it started to rain and didn’t let up much for a week… and hail at times…  not just afternoon thunder showers. Yes, unusual… but it does happen.

Paul where are you finding temperature ranges for within Yosemite? I can find Tuolumne but not along the trail itself. Glad to hear they’ll be in the 70s instead of the 90s! I am still thinking of taking the 40 though. So much less weight and bulk. If I have to sleep in rain gear, so be it.

https://forecast.weather.gov/MapClick.php?lon=-119.177&lat=37.512

NOAA forecast for any location.  Click on the map where you want the forecast for