August temperatures on the JMT

[Drybones]

I was hoping to to hike the JMT in September but can't get the time off except for August, I'm not a warm weather hiker and I'm concerned it may be too hot, can anyone tell me what temperatures I should expect in August, thanks.

[colorado_rob]

We hiked it the first time in late July... it will not be too hot at all, perfect time of year actually. It may be slightly warm in Yosemite near the beginning (if SOBO) or end (if NOBO), once you're up to 8K-13K, no worries.

[wornoutboots]

I hiked it late August last year, starting 8/14 & the weather was perfect! low to mid 70's during the day & upper 30's to 40's at night. No bugs & no rain for the whole 18 day adventure.

[Maui Rhino]

I hiked it 7/29-8/19 last August. It was never "too hot" for me. As already said, you'll be at elevation almost the entire hike, which will keep things cool. My coldest nights got down to 29* twice...both times I was camped above 11000'.

[Coffee]

The only place it is likely to be hot is Yosemite Valley and the climb up toward Little Yosemite Valley and Sunrise Creek. Should cool down considerably at elevation once you get to the Sunrise High Sierra camp area and then you stay up pretty high for a while. May be warm, but not hot, at Reds Meadow. Probably perfect everywhere else.

[imscotty]

Drybones, I got my permit today. I got a Half Dome permit too I will be starting in Yosemite 8/2, I plan on going slow, hope to see you on the trail.

[Drybones]

Thanks to all for the input...hope to see you scotty.

[Dennis Ahl]

Im starting on 7-29 and plan slow also maybe 22 days.

How slow is your slow?

[Malto]

Generally it's really warm and dry but it is dry heat. BUT, I have been snowed on in Early August so you can get just about anything. The later the better in August would be better. The bigger question will be whether you can get a permit.

[MuddyWaters]

Comfortable at 10000 ft
Hot in yosemite valley, very hot.

[Sirsnappy09]

I did it sobo in August and it was hot in Yosemite and a few other very clear sunny days but awesome the majority of the time. I'm going back in August this year and doing a nobo thru.

[verysimple]

70s day time, 30s night. Did it last August


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[ndwoods]

ditto above...once you get into higher elevations you will be fine. 60-70s during the day and 30-40 at night

[Dogwood]

ditto above...once you get into higher elevations you will be fine. 60-70s during the day and 30-40 at night

I'd say more like low 80's to high 70's as day time highs.

[Dogwood]

Generally it's really warm and dry but it is dry heat. The later the better in August would be better. The bigger question will be whether you can get a permit.

Desert and mountain extremes can accordingly have wide temp and weather extremes, sometimes occurring rather quickly.

To add, yes the elevation helps cool things but that's experienced primarily at night when a greater temp and UV range gap occurs compared to during full sunlight periods...or longer duration overcast day light hrs, which in Aug are conditionally infrequent, or maybe fast moving through storms. The JMT is dry in Aug. Plus, overall the JMT offers little shade with open exposure to direct hot sunlight and higher intensity UV at the higher elev. After three JMT's in summer, one in late July one in Aug, being badly sunburned on two of them out of ignorance, now I go in late Sept or Oct. Much fewer people with much less permit competition for the standard SOBO itinerary particularly after Sept 10 or so. Don't kid yourself, it will be day time summer backpacking! During summer heat the JMT is ideal for pre sunrise starts!!!, a 2-4 p.m private siesta, and hiking until after sunset!!! CS's are well known and a spot to cowboy or set up a small tent are easy to find on a map or in guidebooks.


To also add, spent one July 4th, maybe ten yrs ago, in an emergency situation, atop Mt Whitney at the end of a 42 mpd JMT finish, fortunately being able to watch the fireworks from nearby towns. AWESOME viewing fireworks from above! During the day it was in the mid to high 80*'s. At sunset the temp was 44*. One hr after sunset it was 36*. Kept getting colder. Wind picked up. Water bottle froze solid. Day hiker coming up from Boy Scout Lake doing a mountaineer's route was there right after sunset shivering uncontrollably, with no water, in a drenched Hanes T Shirt, no headlamp and little moonlight. Despite the other person and myself emphasizing maybe he should stay the night in the hut both of us willing to share any food, H20, and clothing he went back down, sliding on his arse because he couldn't see.

[Rain Man]

I thru'd the JMT SOBO last summer, 8-28 to 9-21. We had perfect weather and temps. Generally 70s daytime and 40s nighttime. Three nights it dipped to freezing. I was careful not to get sunburned.

[blue indian]

Thru hiked JMT nobo last August starting on the 13th. weather was perfect the whole time. No bugs, chilly nights and warm days. It only rained for like 45 minutes one afternoon.

The exposure can be difficult for some. Plan accordingly.

Have fun and take your time. Its an amazing experience