I have long been a proponent of late summer or early fall for a thru-hike of the John Muir Trial. After my last two successful hikes, I am close to changing that recommendation.
Starting in late August or early September has a lot to recommend it. Most kids are back in school by the latter part of August, and by Labor Day just about all of them are. The deep snow is long gone from the passes. With little snow at the highest elevations there is less water in the rivers and creeks, which makes the stream crossings far less problematic.
I happen to really enjoy two nights—with a rest day between—at Muir Trail Ranch. One- or two-night stays for a single or a small group are far easier to arrange later in the season.
Lastly, I hate mosquitoes. It’s unlikely that you’ll complete a JMT hike in September without seeing ANY of those little bloodsuckers, but you’ll see darned few.
That’s an awful lot of good reasons to hike late in the season. Here’s the one disadvantage: wildfires. During my last two thru-hikes I encountered the smoke from forest fires that came close to ending my trip.
The first occurred in 2009. Two days before I started making my way up to Nevada Fall, a “controlled” burn, near Foresta, became anything but. The forest service was supposed to burn ninety-one acres; by the time the fire was out it had burned roughly eighty times as much (nearly 7,500 acres).
As I ascended out of Happy Isles the smoke wasn’t horrible, but it was noticeable. Three days later, while walking though the Rush Creek drainage, I could hear the build-up of stuff in my lungs. Sleeping was particularly unpleasant, as my noisy respiration kept me awake.
I took an unscheduled rest day at Red’s Meadow and went into Mammoth Lakes to find a doctor. After just one day of some wonderful pharmaceuticals I was nearly 100% and back on the trail.
In 2013 it was the Rim Fire. (This fire would ultimately dwarf the fire of 2009.) The Rim Fire almost disrupted my hike before it began. I acclimated in Mammoth Lakes, and if I had waited two more days before taking the YARTS from Mammoth to Yosemite Valley, I would not have gotten through. The road closed about forty-eight hours after my trip.
Then, on the fifth day of my hike, the wind changed and all the smoke that had been blowing northeast started to blow south. When I reached the top of Donohue Pass I could hardly see the terrain behind me.
I exhibited no symptoms of smoke-inhalation this time, but walking through all that smoke (while breathing hard) just wasn’t much fun. Fortunately, the smoke cleared the next day.
Twice more during the next two weeks the wind would change and spoil the air (and the views) during my hike. Each time I considered abandoning the trail if things didn’t improve within a day or two. Each time they did improve.
One last comment regarding the upcoming hiking season: right now we have a tiny fraction of the snow we might normally expect. Oh, and we have higher temperatures than normal as well. At the rate things are going, this could be a very bad year for fires.
So, is all of this a good enough reason to hike early? I don’t know, but it is something you may want to consider. If you decide on a June or July adventure, just make sure you bring the insect repellant!
Good hiking, Ray