A few years back, we were visiting Las Vegas with friends. We decided to rent a boat and go out on Lake Mead. It was probably 70's out and in March. The lake was deserted!!! There were maybe 2 or 3 boats out. We spoke to the conservation police officer on the water and she explained that the locals thinks it is too cold to be out. It was a great day out on the water! We wished we had left earlier so we could have explored the Colorado river...