Blooms of blue green algae have already been reported in parts of Canandaigua and Honeoye lakes.
New York State Department of Health reported that this week, and advocates for local water quality say long, dry stretches of weather are prime makers of HABs.
The algae, which can be toxic if ingested by humans or animals, was found in designated swimming areas of Butler Beach on Canandaigua Lake and Sandy Bottom Beach on Honeoye Lake.
Both of those beaches are shut down to swimmers.
The algae can produce toxins that can create health risks to people and animals if they are exposed in large enough quantities.
Symptoms can include allergic reactions or eye, skin, nose, and throat irritation.