Having known the east coast most of my life, swarms of various insects seem to happen all the time from Spring on.
One year there were, what I call, thunder bugs and these are quite large and black and aim for bright TShirts. We often get swarms of ladybirds and they will create a carpet all over buildings and the ground. This year we've had these tinny black beetle like insects that have covered my flowers and the washing on the line. Flying ants seem to happen everywhere, especially if it's been wet and then we get a hot spell that makes them all hatch out at once.
Crane Flies (Daddy Long legs) usually emerge in late summer. Wasps are just a nuisance at any time during the summer!!
Stellajane - I don't think you can expect there to be insects of the beach all the time - it will be about the weather and the life cycle of certain insects and nobody will know when or where they will plague us. A lot of the swarms are coming from Europe on the wind. We may be doing Brexit but it won't stop us getting their wildlife and pollution. DG x