It may be warm during the day in the park. After the sun goes down and our Bay Area fog and breezes arrive it can get mighty cool at night. Please bring a med jacket and blanket to take away the evening chill.
The City of Oakland manages the parking in the park on performance nights, and there is a $5.00 fee for parking in the lots around the theater. You may park on Joaquin Miller Road for free, but be prepared to walk a considerable distance to the amphitheater.
The weather was warm.. I wore a long sleeve top and decided around 10PM to put on my sweatshirt. Didn't need the blanket we brought, bu then it's nice to sit on it for extra cushion on the plastic seats..