The shutdown was enacted "as a precaution while the storm cell moves through," the city of Newport Beach said in a tweet shortly before 9 a.m. The beaches were reopened as of 10:45 a.m.
Officials warned that the weather in the area was still unstable and changing, adding that lifeguards were assigned to continue monitoring the coast throughout the day.
Lightning and thunder continued to bedevil areas throughout Southern California on Wednesday, rattling some people awake while making for a wet morning commute in some communities, most notably in eastern and northern reaches of Los Angeles County.
As the day progresses, conditions are expected to be generally warm and muggy, thanks to the monsoonal moisture.
"It's likely that most areas will end up 4 to 8 degrees above normal,'' according to the National Weather Service. "It will also be a little more humid, making the above-normal temps feel a little worse.''
A chance of showers and thunderstorms will continue as the storm system moves off to the northeast. Calmer weather conditions are anticipated Thursday, with mostly sunny skies but a small chance of some isolated showers thanks to lingering moisture.
City News Service contributed to this report.