The Hay Day

WLS and WCFL were considered "clear channel" stations which I believe means they were the only one on the frequency they used, so they were allowed a higher wattage. In '73 I went on a trip to Reno from Chicago. We were well into Neb. before we lost the signal from WLS.

The weather does have an effect on how far a signal can go. I think cold and clear will do it, but so will foggy conditions. I can remember two times where it was foggy out, one in Chicago while riding around in a friends 57 Chev and dialing the radio around and came up with a strong signal from Boston.
Another time on a camping trip in Wis. and again came up with Boston on a portable radio. Maybe the Boston station was a clear channel too.