I was using 2.1.3. I updated to 2.1.4.
I also now have a slightly better understanding of how wunderground gets its data. I was using a nearby weather station that, presumably, does not have a rain meter installed because it would always only show “– mm” rather than a figure. I changed to one slightly further away, and it then showed “0 mm” so hopefully that fixes that part.
Now the sun rise/set times make a little more sense (though they are not entirely accurate) and my % is showing 4%. Whether or not that makes sense, I’m not sure… but at least it is doing something.
I might consider getting my own personal weather station since the ones in my area are all too cheap to have a rain sensor 🙂
Thanks for your help.