Is Lake McConaughy safe to swim?

As of July 20, 2026, Lake McConaughy in Keith County, Nebraska is clear to swim. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Rainfall over the past week totaled 0.0 in, which can wash bacteria and nutrients into the water.

How this read is built

Lake McConaughy is a lake in Keith County, Nebraska covering about 38.9 sq mi, the 1st-largest of the 75 lakes SwimZone monitors in Nebraska. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Larger, warmer waters like this can hold a bloom for weeks once nutrients and calm weather line up.

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, Lake McConaughy has reached blue-green algae advisory levels in 1 of them, most recently in September 2025. Blooms here have been occasional rather than annual. Its highest recorded reading was 274,931 cells/mL in September 2025.

Is it safe to swim in Lake McConaughy right now?

Lake McConaughy is clear to swim today. Satellite imagery detected no blue-green algae bloom as of July 19, 2026. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.

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

No blue-green algae bloom is detectable at Lake McConaughy as of July 19, 2026 (below the satellite's roughly 10,000 cells/mL detection limit). Cyanobacteria can still appear within hours in warm, calm, nutrient-rich water, so look before you swim.

Can dogs swim in Lake McConaughy?

No bloom is detected at Lake McConaughy 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 Lake McConaughy have blue-green algae blooms?

Over 7 summers of satellite monitoring since 2020, Lake McConaughy has reached blue-green algae advisory levels in 1 of them, most recently in September 2025. Blooms here have been occasional rather than annual. Its highest recorded reading was 274,931 cells/mL in September 2025.

How many Nebraska lakes and beaches are unsafe for swimming today?

Today, 44 Nebraska waters are above a safe-contact threshold and 4 more warrant caution, out of 83 monitored waters SwimZone tracks in the state.

How is Lake McConaughy'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 Lake McConaughy, and a recent-rainfall overlay, all refreshed daily. It was last updated July 20, 2026.