I had a party once with my speakers in the garden, giving the best sound I have heard from a hifi system ever:
As you’ll note from that, the amp and source remained indoors, just the speakers outside. I pulled thin plastic bags over tge speakers to keep out dew or unexpected rain, which made negligible dofference to sound. However I’d be wary of having wood veneer speakers outdoors in the British climate for any extended period of time.
Aside from all that, an issue with playing music outdoors is disturbance of neighbours. My solution with the party was to invite them, but otherwise with immediate neighbours I would never play music outdoors (and windows are tight shut when playing indoors). We have some inconsiderate neighbours a few doors up the street who often have people round in the summer, playing music outside, and it is very annoying as when they do that they destroy our peace and quiet if we’re sitting in the garden.