Although the ionosphere is much higher up in the atmosphere than, for example, thunderstorms, local rainfall can affect the ground conductivity. That item was of particular interest to me, as over the years I have experienced many examples of this phenomenon. To take just one, in the mid 60's when I lived in Eastern England, I used to be able to listen to the offshore station Radio Scotland during the day when there was a lot of wet weather about. The station was about 300 miles away using a 10kW transmitter. On hot sunny days in mid summer, the signal was very weak, sometimes inaudible.
Wet weather does indeed have an effect on ground conductivity.
If you're interested in studying this phenomenon, you need a reliable station list. Some are reviewed elsewhere on this Web site. Continue to the Clubs and Pubs section for details.