Recent shipping rates have skyrocketed as much as 187% over equivalent China - US West Coast shipments from the previous year, and as much as 84% over China - US East Coast shipments.
There are several contributing factors that could explain the rise:
Alternate shipping patterns/routes created during COVID lockdowns have not fully shifted to their previous ports/routes, creating an under-supply of container ships at larger ports
Production and shipping delays caused by COVID shutdowns, along bumps in ecommerce sales have created some backlog in containers leaving China
As a result:
China officials have requested that cancelled sailings be restored and pressured state-owned carriers reinstate their blanked sailings
Maersk & Hapag-Lloyd have added or restored capacity
Carriers have cancelled or reduced their scheduled September rate increases
Also consider:
There was likely a bump in demand leading up to China's Golden Week holiday
The prospects for future volumes and activity remain mixed. Predictions vary from strong stable volumes for the remainder of the year, to steady declines for the remainder of 2020.