Dan's 6 liters of water is about right -- that is, it is about the right amount to drink. I would never carry it from the trail head, though. For most people, the extra weight is a sure way to reduce your chances of going all the way. The other part of this: Make sure
you drink lots, and regularly, as you go. Most people, myself included, just don't feel that thirsty, so I force myself to drink, usually twice as much as I think I need. ...you need to drink enough so that you need to pee every 2-3 hours. If you can go 4-5 hours, you're not drinking enough.
It's a good idea to take electrolyte tablets along, too. I like to mix Nuun tablets (even saw them at my local grocery store the other day) with lemonade drink mix. The tablets make the drink taste carbonated!
For myself, I dip and drink from just about every stream along the way. This has always worked--never any intestinal distress (which would show up about a week later). Doing that, I can get by with all containers empty, except for a small ~12 oz water bottle that I use for sips along the way.
Here's Bob R's "water sources
" document, his map
, and pictures
As for temperatures, the closest actual guage is just south at Cottonwood Lakes. Find the link near the bottom of the Whitney Weather page (link above on the left):
Cottonwood Lakes, elev. 10150' 7-day Temperatures
. Check it just before you go. ...Looks like it failed on 8/2 ;-(
Here's the Crabtree Meadow station
, west side of Whitney, at 10,700