Much of this week in the interior valleys we've experienced 100-105 degree highs, up to 10 degrees above average. Not only is a cooldown developing but temps early next week look below average.
The coast has the same downward trend but since some marine influence was already around the drop may not seem as significant.
Beaches have had a lot of night and morning cloud cover with some stubborn marine clouds at some beaches. More of the same for beaches with a minor downward trend as well.
All of this starts Saturday at beaches and near coastal valleys but inland temps only ease down a little Saturday with a more significant drop Sunday. It just takes some time to get the modified air going into the valleys.
Sunday thru Tuesday look cooler than average everywhere with models suggesting warmer temps into the following weekend, potentially HOT inland again.
The reason for the change is the ridge in the jet stream is sliding east and SW upper air flow sets up. In the summertime SW flow aloft is a mild direction.