Late Season JMT hike Sept 16-30

Weather in late September can be quite stable in the Sierra – I’ve backpacked and day hiked in the last two weeks of September quite regularly since around 2001. Nights could be quite chilly with night time temperatures dropping into the teens with morning frost.
Daytime temperatures are usually pleasant depending on altitude. Wind can always be a factor especially on peaks and the higher passes. Late September also means fewer hours of daylight.

I don’t see any reason why you couldn’t summit Whitney unless there’s a storm that day.
Every once in a while a tropical disturbance may cause a storm to dump snow or rain – last time I was caught in one such storm was in 2005. But such storms are usually fast moving and are gone in a day.

You ought to consider starting at Horseshoe Meadows (easy to get walk up permits) and go over Cottonwood Pass and spend a night at the trail head which is at 10k. Avoid starting on a weekend day – the trail head campground is not crowded at all in late September on weekdays. It will add a few miles but will let you acclimate much better. Also, you’ll have a better feel for the weather 2-3 days out when you’ll be close to Guitar Lake when you’ll be close to summiting Whitney.

In any case it will be a great hike; please do post your trip report here!

Thank you for the info @pedestrian!

We would like to go SOBO if possible, but considering NOBO.  If we go SOBO we will be staying overnight at TM/ Lyell canyon at 8500-9500 ft elevation before the hike. We have never had any issues being at 10k feet so we hope going SOBO will acclimate us enough for Whitney.  Thank you for the suggestion re horseshoe Meadows, we will be looking into that as another option as well.

Ben

I think going sobo out of Lyell is a great idea. You’re right that it’s easier to acclimate that way. If you can spend a night at Tuolumne Meadows, or for that matter just hike in the first 6 or 7 miles of Lyell, which is flat, you’ll get a leg up on acclimation. Donohue isn’t too high, and then you spend a few days at still lower elevations before climbing again.

It’s true that you’ll have shorter days and cooler temps, especially at evening/overnight. Most likely you won’t have to face much or any precipitation. I live in Berkeley and am usually hankering for snow in the mountains at that time of the year. No luck! It’s still way off–Thanksgiving or thereabouts. So leave the Kahtoolahs  behind for sure.

Just came back from Thousand Island area – very dry air making your nose and throat dry and painful. Some mosquitoes around water sources. There is some snow here and there and you may need micro spikes on some passes, but we didn’t cross any so don’t have full info on this. Most people on trail didn’t seem to carry spikes.

Some quick thunderstorms with rain, but nothing major this weekend.

This is my favorite time for the Sierra.  No on the microspikes, if there is snow then it would fresh and microspikes would not be of much help.  I have been snowed on every month of the year in the Sierra and often early season storms will catch hikers by surprise.  I would watch the weather forecasts at every opportunity.  Have a great trip, it is a truly magically time of year in that range.

Just got back from the Sierra with Tom K, went over Shepherd Pass and wandered about the Kern (crossing the JMT). No issues with snow. Plenty of water. Certainly plenty of mosquitos.

Here’s a pic of Whitney in the background. Looks okay as far as snow.

For a late season JMT hike be sure to check on resupply end dates for various locations and for details such as: there can be an extra $$ charge for resupplies late in the season-check on VVR for example. I believe the Florence Lake ferry is no longer in service. These examples shouldn’t stop you from a great trip but it really helps to know in advance what you’ll find once you’re out there on the trail.
Hope you have a great trip and that the weather is fine. You may see some lovely Fall colors.

Doug,
I’m sure your trip with Tom warrants a Trip Report. Please. Craig W. gave us some great photos of his trip with Tom but not much text. Some of us can’t do these trips but we love hearing about them and seeing photos.

Would mention (for anyone else thinking of a late season trip up Sheppard’s) that there is a snow field on Sheppard’s pass that covers part of the switchbacks but you can cut the switchbacks to avoid it. A bit of a pain but not a huge issue. Was just up there last week. Also could see from the bench before Junction Pass that there are some small/short snow fields over the trail up Forester. Didn’t look too bad though and I think some people had created a second trail to avoid it.

Had no issues with mosquitoes pretty much but we camped high almost every night. Weather was very finicky. Cold winds during the day, clouds trying to get together for a shower most days, big thunderstorms on the night of the 11th for 4 hours…weird weather pattern but hopefully it’s moved through. Nights weren’t cold at all however. Weather report was pretty useless