Also I would like to know the avg. temps for this time of year too.
Here is some info from the CA Dept of Water Resources/Snow Surveys station @ 10150' located at Cottonwood lakes:
2014 2013 2012 As you can see dipping down into the 30s isn't uncommon. Throw a little wind & rain in there and it could be a chilly night.
This year, Whitney got some snow during the first week of August:
Current Conditions: Mt Whitney Trail 
