Such a lovely illustration, that really tells a story. I don’t know whether the greyscale was a requirement of the illustration, or your own choice, but it works very well to set the mood – especially with the fade in detail and contrast giving that feeling of heavy rain and clouds and their effect on the visibility.
The fade in contrast could possibly be a little more evenly applied to the water and sky as to the figures, but the focus on the two right-most characters is still good and strong. Those streaks of rain must have been fun to do! I also like how you’ve not been afraid to obscure some of the characters’ features with rain, keeping that feel that we’re in there with them.
I’m not entirely sure about the front-most character’s grip on her paddle – the left hand doesn’t look quite natural, and I think I’d expect the boat to be pulled up a little further on the shore before they stepped out, since the waterline makes it look like both characters are ankle deep in water. But these are minor niggles when the overall illustration conveys the mood so well.
And I can’t leave without mentioning the background. I’m blown away as ever by how natural you make your settings look. The rocks, the trees, the raindrops on the boat, and the texture of the bare earth – it’s so real. Great stuff!