Authorities are warning boaters from Lake Huron to Lake Erie to be mindful of cold water dangers while enjoying warmer weather.
Air temperatures are topping 80 degrees a few days this week, but the Coast Guard says water temperatures only are in the 40s and 50s.
Risks include drowning and hypothermia. The Coast Guard says cold water can cause muscle cramping, increased heart rate, elevated blood pressure and death.
Sector Detroit Response Chief Cmdr. Robert Berry says boaters "should be prepared for emergencies where they might find themselves unexpectedly in the water."
Life jackets can prevent someone who has fallen into the cold water from being fully submerged.