Is Cherry Lake safe to swim?

As of July 20, 2026, Cherry Lake in Clark County, South Dakota is clear to swim. Satellite imagery measured 13,212 cells/mL of blue-green algae on July 19, 2026, well below the 100,000 cells/mL advisory threshold. Rainfall over the past week totaled 0.0 in, which can wash bacteria and nutrients into the water.

How this read is built

Cherry Lake is a lake in Clark County, South Dakota covering about 0.5 sq mi, the 102nd-largest of the 127 lakes SwimZone monitors in South Dakota. Satellite imagery measured 13,212 cells/mL of blue-green algae on July 19, 2026, well below the 100,000 cells/mL advisory threshold.

Blue-green algae (cyanobacteria) blooms are most common from midsummer into early fall, when the water is warm, calm, and rich in nutrients from runoff. They can produce toxins that make people sick and can be rapidly fatal to dogs, so skip water that looks green, scummy, or like spilled paint, and keep children and pets out of it.

Over 7 summers of satellite monitoring since 2020, Cherry Lake has not reached a blue-green algae advisory level. Conditions can still change quickly, so check the current read before you swim.

Is it safe to swim in Cherry Lake right now?

Cherry Lake is clear to swim today. Satellite imagery measured 13,212 cells/mL of blue-green algae on July 19, 2026, well below the 100,000 cells/mL advisory threshold. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.

Does Cherry Lake have blue-green algae (cyanobacteria)?

Low levels. Satellite monitoring measured 13,212 cells/mL at Cherry Lake on July 19, 2026, below the 100,000 cells/mL advisory threshold. Keep an eye out for surface scum, which can concentrate quickly.

Can dogs swim in Cherry Lake?

No bloom is detected at Cherry Lake today, but dogs are much more vulnerable to blue-green algae than people, and blooms can form within hours. Always keep dogs away from water that looks green, scummy, or discolored, and rinse them off after swimming.

How often does Cherry Lake have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Cherry Lake has not reached a blue-green algae advisory level. Conditions can still change quickly, so check the current read before you swim.

How many South Dakota lakes and beaches are unsafe for swimming today?

Today, 89 South Dakota waters are above a safe-contact threshold and 3 more warrant caution, out of 142 monitored waters SwimZone tracks in the state.

How is Cherry Lake's water quality measured?

SwimZone builds this read from EPA CyAN satellite imagery for blue-green algae, official beach and fecal-bacteria advisories where a program monitors Cherry Lake, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.