Backpacking Night Temperatures

[x-countrycamper]

Hi all, I'm backpacking out to Ostrander Lake in Yosemite with my dad this Friday 10-1 to Sunday and had some questions on night temperatures. This is the first backpacking trip my dad has done in several years and he's feeling very excited now that he has recovered from his hip surgery last year and is able to enjoy more of the outdoors.

First question I have is that I've seen very different weather reports for the area from different websites.

For Ostrander lake from the national weather service Friday night shows a low of 44, where Google shows that the low for Ostrander Lake is 33 on Friday. I trust NWS much more but the difference is quite significant.

https://forecast.weather.gov/MapClick.p ... U9cCZrMKUk

https://www.google.com/search?q=ostrand ... e&ie=UTF-8

Next, why dose the Tuolumne meadows show to be so much colder?
The national weather service temp for Tuolumne meadows shows a low of 23 on Friday night.
The elevation for the two locations is almost the same, I've read that cold air goes down into valleys at night do you think that this would be the cause of this difference?

Has anyone had success or tried using the hot rocks in their sleeping bag or tent to stay warm at night? what other suggestions or tricks to you use to stay warm at night?

Also am I correct in my understanding that Yosemite is allowing fires in existing fires between 8,000 and 9,600 ft.? I couldn't find any information saying this was not the case but was pleasantly surprised when I read it on their fire restriction page.

Thanks so much for you Advice information and answers!

[neil d]

Hi, we just dealt with a similar discrepancy in predicted temperatures during our trip northward from Tuolumne Meadows last week.

- I've always felt NWS is the 'gold standard' for realistic temperature forecasts, and they were very reliable last week. To get very specific, I plug in a location in the search box (like Tuolumne Meadows) and then use the map window on the right side of the forecast page to zoom in and click on my specific destination. This approach has been very reliable through the years.

- We also saw that the forecast lows for Tuolumne Meadows were about 10-15 degrees cooler then our destinations, even though our destinations were about 2k feet higher in elevation! I attributed that to what you describe, cold and cooling air descending into the valleys at night. But our last night was spent right next to the river below Glen Aulin, and temps were quite comfortable! So who knows. Regardless, I'd be ready for upper 20s.

- I would not trust gimmicks like hot rocks to stay comfortable in low temps. Instead, bring the appropriate gear. What I do: bring a just-large-enough tent, quality insulated pad (actually two), and warm sleeping clothes (especially a hat, and my comically thick and fluffy socks, as my feet tend to get cold). Perhaps most importantly, I try to have a high-calorie meal at least an hour before bed, and get in bed before I am shivering cold. This time of year, when the sun goes down in the mountains, it's bedtime.

Regarding fires...and I'll try and be careful here...you are correct, that NPS currently allows fires between 8k and 9.6k feet. And I find that unconscionable, given the potential risk and current state of affairs. Speaking personally, my nights of backcountry campfires are about done, both due to increasing wildfire risk and general LNT principle. But, they are allowed, so do what you will!

Have a great trip!

[rlown]

Don't do the fire. Not worth it and you don't want to be "that guy" who started something in a tinder dry area.

[SSSdave]

This shows recent temperatures over the last 20 days with lowest recently only 43F.

https://cdec.water.ca.gov/jspplot/jspPl ... ies=cdec01

As to why, that is obvious looking at caltopo:

https://caltopo.com/map.html#ll=37.6238 ... 3&z=15&b=t

Ostrander Lake is at a modest 8,505 feet with the tiny north facing basin above it only 9,200 feet on Horse Ridge. So very little night cold air sumping possible. On the other hand, Tuolumne Meadows at 9.5k has a vast area in its basin above to over 13,000 feet including many high areas at this time of year that due to the low sun altitude are in shadows all day thus each day are becoming colder and colder.

Your post reads like someone with marginal sleeping bags. If so one can always bring extra blankets and warm clothing especially head gear like a balaclava. Instead of making a fire just plan to be inside your tent and sleeping bag by dusk. The night is really long by October so you might bring a radio along to play in the tent.

[x-countrycamper]

Thanks so much for the information! I had a extremely cold night when I went backpacking two years ago. I upgraded much of my gear last year thankfully before I went backpacking again but it was so warm that I slept on top of my sleeping bag, granted that was at the end of July and it was 112 that weekend in the valley. I find it amazing how much the landscape makes a difference between Ostrander Lake and Tuolumne. I'll post a trip report next week after my trip.