Summer is usually the peak wildflower season in the Yosemite high country. Although early bloomers like shooting stars appear in June, flowers are typically most abundant in July at elevations between 7000 and 9000 feet. Heavy snow the previous winter can push this peak back into August. This past winter brought average snowfall, so I'd usually expect an average amount of flowers with the peak in July, but the cool and wet weather might delay the bloom and maybe, just maybe, make the flowers more abundant than usual.
The photograph above was made near White Wolf in July of 2004 after slightly below average winter snowfall.