You seem to be getting fairly consistent responses, so let me chime in:
1) Understand that the weather on Whitney can change by the hour. You should prepare for the worst conditions and then if you're pleasantly surprised no harm done. Yes the day before weather will give you 70% of reality, but 30% is a lot.
2) whole heartedly consider bringing crampons and ice-axes, and learn how to use them. Read the chapter on snow/ice traversing in Freedom in the Hills or otherwise understand how to use them. Practice at home and at Trail Camp in the lower part of the hill before you go up the switchbacks.
3) Be careful, IMHO of the area right below Trail Camp, the switchbacks (especially the cable area), and right past the peak of Trail Crest headed towards the JMT and summit. IMHO those are the worst 3 areas.
4) Follow the weather daily, and ask others who exit the trail if you can before you head up.
5) Take as much crap (crampons, ice axes, snowshoes, helicopter
) with you to Whitney Portal, and leave behind what you decide you don't need - but it's best to take more than you think you need.
6) Extra Hydration - walking in snow is extra tiring. If you get thirsty it is too late, you are already dehydrated. Drink often.
7) Plan for cold weather, but every bit as much, high winds. The winds can cut through gloves and hats mostly and leave you cold to the bone.
8) Attempt the summit, fine. But make decisions about the next leg on the current leg. Get to Outpost Camp. Get to Trail Camp. Get to Trail Crest. Get to the Summit. Give yourself a green flag on each leg, and go. Give yourself a checkered flag, and call it a day.
9) Get off the damn summit early. Storms do tend to come in in the early afternoon or later. These being the times they don't come in earlier.
10) Use your common sense. How is everybody feeling? Does everybody have gear and know how to use it? Is it needed? Is everyone comfortable with what they need to do? What's the sky look like? What time is it? What are other descenders saying?
11) Go over in your mind the scenario where you turn around at Trail Crest, or other locations. Feel good about it. Give it real consideration.
12) REMEMBER, you have to go back down what you went up, and it may look and actually be (due to melting/freezing/weather) much different by the time you get to it on the way down. Think about this as you proceed through/by each area you consider difficult. Last time I summitted was in June, and the cable area was no problem or even consideration going up, but on the way down we scooted down on our butts on the water-covered slippery ice.
13) Read as many comments on this forum as possible.
I've probably forgotten 50 things.
Have a good time, and good luck.
Cheers,
Jeff Long
