I don't say painting in rain is fun or easy. But it can deliver. And that's what it's all about.
➜I used to wait for a 'good day to paint' but most of the time this will mean you'll miss out on a lot. So don't let 'fear of getting wet' hold you from painting: the umbrella will only keep the painting dry. The palette you'll just have to shake once in a while to get rid of the water. Oh yes: that's why oils are better to work with outdoors: you can't do this with acrylics.
(And did you ever wonder what happens to the plastic molecules you throw down the drain after painting with acrylics? Indeed! I think acrylics are bad for the natural environment, because who says they can get these plastic molecules out of the water again? ->Perhaps they can't. Think about it. These things I think about.)
All weather can deliver, just dress warm & bring the duct tape + umbrella :)
Here's one more, literally painted in pouring rain:
LSU05-2016 Cows in Rain Going Home (sold)