The letter was sent to the governor asking for the state to make a change.
The city leaders say with parks staying closed until their counties reach the yellow tier, this could mean over a year-long closure, which would threaten thousands of jobs and economic recovery in their communities.
The affected theme parks include Disneyland and Universal Studios Hollywood.
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RELATED: Disneyland's ongoing closure could ultimately cost SoCal economy $5 billion
The letter also states that labor unions and employee groups representing the employees at these theme parks have joined in calls for a safe reopening.
Los Angeles County is in the purple, most restrictive tier, and Orange County is currently in the red.
The letter also asked for Newsom to work with coalition members of San Diego, Anaheim and Los Angeles to discuss the reopening of large theme parks at a reduced capacity in Tier Three rather than Tier Four.
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