This is the National Weather Service weather report for this weekend, at Whitney Portal.
Friday: Sunny, with a high near 58. West wind 15 to 18 mph decreasing to between 6 and 9 mph.
Friday Night: Mostly clear, with a low around 42.
Saturday: Sunny, with a high near 55.
Saturday Night: Mostly clear, with a low around 39.
Sunday: Sunny, with a high near 55.
Sunday Night: Mostly clear, with a low around 39.
That sounds like sunny pleasant days, with decreasing wind and below freezing nights up on the Mt. Whitney Trail.
Have a great trip and please post photos if you can.