Agree. Too hot in the desert.

If you want the best of CA Hyatts during August, I'd rec the following (north to south):

HR Lake Tahoe Resort (technically in NV, but a shame to miss Lake Tahoe on a CA trip)
Hyatt Vineyard Creek Santa Rose (wine country)
HR SF
HR Monterey or Highlands Inn
Mar Monte (Santa Barbara)
Andaz WeHo
HR Huntington Beach
PH Aviara
Andaz SD (if you want party scene in Gaslamp District of SD) or HR Mission Bay (if you want a place a bit more relaxing)