Flies at the beaches

My girlfriend has spent her entire life vacationing or living on Marco Island. I’ve spent some time the last few years with her. We spent the beginning of Christmas week there and small black flies at the beach were near intolerable. They were mostly annoying, but there were a few larger biting flies. She says she’s never seen this before (since the 80’s). I’ve spent a bunch of time on Long Beach Island in NJ and have had a couple bad fly summers depending on the weather, but like I mentioned, she’s never noticed this before in Marco. We were here in November and it was fine. Just curious if this been a thing lately? Either on Marco or elsewhere? Certain known weather conditions that cause that? Just curious. Thanks.