A very wet morning here in Devon. Hope it is nicer where you are.
For ages, I didn't attempt a painting like this because I couldn't figure out how to paint rain. I was thinking, it is so - visually - intangible. How do you capture it in something as tangible as oil paint?
Rain doesn't have shapes or lines or edges. It is just kind of blurr-y.
Then I had the ha-ha moment.
Wait a bit for the paint to tack up. Take a firm bristle brush - I often use one of my old ones where I have cut away some of the bristles so there are only a few raggedy ones remaining - and carefully drag it through the tacky paint in the direction you want the rain to be coming from. Sideways, in this instance.
The rain always falls sideways in Devon.