That sounds about right for that time of year.
We went over NAP on mid September and saw two or 3 people and 20+ deer from the top up the pass to Lower Trail Crest. The weather was absolutely beautiful until summit day...<10 F with 30 to 40 MPH winds. It was in the 70s when we reach WP that early afternoon but Mt. Whitney was experiencing big ass electrical storms.
If you don't like the weather in the Sierra, wait 5 minutes.
