Jmt in May?

In a typical year, in early may about 90% of the JMT would be snow-covered – about the only part not covered would be the San Joaquin canyon, the bit from Happy Isles up to the top of the falls, and the last thousand feet or two down to the Portal. In late may, probably 60 or 70% would be covered. Could you do it in late may of a typical year without skis or snowshoes? Yeah, you could; you get up before dawn and make your miles while the snow is hard – after the early afternoon you'd be postholing something fierce. But the big nasty would be stream crossings – the creeks are running at maximum and would be pretty dangerous in some cases. Bugs – usually not a problem yet in May. Resupply would be complex – none of the usual spots – Tuolumne, Reds Meadow, VVR, or MTR – are operating in May.
In a light snow year or early melt year, the trail itself would be easier – though the streams still nasty – but the resupply story would be the same.
Having pondered a thru-ski of the JMT, I've looked pretty long and hard at the resupply situation and at the stream crossing issues, and discussed then with a friend who has skied the JMT. If I were to try to ski it, I'd go off route in some sections to stay higher up some drainages to avoid the worst crossings

Now, in a big snow year, in late may it's all skiing. Here's how it looked at Sapphire Lake on May 24th 2011

I was the first "hiker" that had gotten over Glen Pass on the 1st weekend of May 2013.
This was a low snow year and there were no ones footprints.
People may had gone over earlier with crampons and an ice ax, but we were the first hikers.
It hadn't snowed up there for a few weeks and the snow was melting pretty good the 2 weeks prior to us going.

So on a low snow year it's doable.
On any other year you're looking at 50% snow coverage above 9,000' and almost 100% above 9,500'
Since the average elevation of the JMT is 10,500', you're looking at a lot of snow.

Don't know why in the world you wouldn't want snowshoes in those conditions?

It's not that I mind snowshoes…its carrying them 220 miles that seems hard.
Was hoping to start in either in sept or May to avoid the crowds/mosquitos.
Sept was my original plan…but some family stuff came up that might prevent that….so I'm looking for a plan B. …given the info you've shared so far…this might me tougher than I thought…

Another way to look at it is to remember that Memorial Day weekend is often the first time that the highway across Tuolumne Meadows is plowed. Do you really want to start SOBO on the JMT weeks before they can get Route 120 open?

You never can tell — varies year-to-year, but when you have to plan so far ahead ….

–MV

Remember too that the traditional resupply points open when they have always opened, regardless of the snow levels. Going earlier than they open can mean a pretty heavy pack or some quite lengthy side trips to get food.

"Just curious, anyone ever try the JMT in May?
I know it depends on the year…but…yeah…just curious if it was doable without snowshoes/skis."

May is pushing the envelope, even in a low snow year. However, we're going on 3 low snow years in a row, and that may change things a bit. We went in over Taboose Pass in the first week of June this year, and the JMT was clear all the way up to Mather Pass and as far as we could see to the south. That said, more snow typically falls the farther north you go, so what we saw may not tell the whole story. If I were you, I'd keep a close watch on snow levels at various points along the JMT, and if it turns out to be another low snow year come spring, go for it with micro spikes. Depending on how much mileage you cover daily, and how much food you require and can carry, you could resupply at Red's Meadow or Mammoth, again at Bishop, and if necessary, Road's End or Independence. These resupplies would slow you down some, so it also depends on how much time you have to do the trip. One thing for sure, you'd be facing some interesting stream crossings in June of a low snow year.

So, my son hiked the PCT this summer. We resupplied him going over Kearsarge Pass to Charlotte Lake. It was June 16th, 2014. This year I think ended up being 14% of normal snowfall. On the way up Kearsarge we hit very little snow, with no snow at the pass or down the west side.

My son and his hiking partner had come over Forester Pass and hiked in snow a few miles above Tyndall Creek (Diamond Mesa?) It wasn't hard hiking as the trail was well traveled. The south side of Forester was pretty clear but the north side had a lot of snow and they glissaded down the whole thing. Glen had snow and was a bit sketchy. The only other pass they seemed to say was tough due to snow was the approach to Muir.

A week later my wife and I hike with them from Reds to Tuolomne and we only encountered snow on either side of Donahue. Now, that was in a REAL LOW snow year.

Backcountry ski groups plan trips in the High Sierra in late April to early May on a normal year (like the Sierra Haute Route).

The real problems are:

Snow travel is real slow and you may have to plan travel according to weather, i.e. hard snow to not have to post hole all day. Snowshoeing is a slow hard way to travel in snow; trying to make the distances you need to make each day for food rations, etc.
Resupply points most likely will not be open in May.
Crossing rivers during runoff can be much more treacherous.

I am sure there are some more to think of, but, those are a few I can think of. It is doable but it become a different type of trip with a different type of planning. Too bad you can't make it is Sept. That is such a great time to do the JMT.

Good luck in your planning.