I made that hike late July, 2004, and spent the third night on the summit of Mt. Whitney. Got this great sunset picture:



If this dry winter continues, you will be lucky to even step on snow. Or what wbtravis said above. Watch trip reports and weather between now and your trip.

The place to keep in mind is the south side of Forrester Pass. But I doubt this year it will be significant at all. The north side is gentle, so even in snow is no trouble. The south side is blasted out of a cliff, so with a major load of snow, could be dicey.