Oh dear - here we go again. Another one saying that other people will be causing a spike due to their behavior. Had this said so many times over past few weeks.
Of course people are much safer from virus infection in the open air - not sure as to their safety from sun burn though today . Traffic jams are horrible and uncomfortable - but do not have any effect re . the virus.
People try to social distance - within their own groups - on the beaches - I have personally seen people doing this, a long way apart from each other, and newspaper photos of the same beach at the same time (using special lenses) showed them all crowded together.
Not sure I would like to be on any beach in this heat. But, do not think it will have any effect on increasing infection rates.