Tioga pass was still closed when we went in April, still had 6ft of snow on the pass roads at that point.

Like you say though, it's a different world, we went from 100 degrees plus in Death Valley in the morning to 4-5ft of snow still lining the road into yosemite above 4000ft. It's mind blowing stuff. It didn't really register on the drive into Yosemite, just how the elevation is so high. It was when we were leaving the park and heading to San Fransisco that it really showed up, we must have been going downhill for about half an hour beside the river, stunning.