Public access isn't available to most of the LinkedIn posts which provided feedback to this question, so I'll list the feedback I received here.
I must preface this by saying that these are the opinions of people who shared their thoughts with me. I am in turn sharing this with you, appreciating that music is very much about personal experience and taste. I would not wish to filter this list to exclude something you may also enjoy when the rain is falling around you.
So, in no particular order, here we go - 10 songs to listen to on a rainy day:
1. Sketches of Spain - Miles Davis
2. The Fountain soundtrack - Clint Mansell
3. Beneath An Evening Sky - Ralph Towner, Slava Grigoryan, Wolfgang Muthspiel
4. Summertime - George Gershwin
5. Pink Moon - Nick Drake
6. Rainy Nights In Georgia - Brook Benton
7. Monument - KiloWatts
8. Ommadawn - Mike Oldfield
9. It Feels Like Rain - Aaron Neville (composed by John Hiatt)
10. Cumulus Rising - Alex De Grassi