I bought your assets and saw the weather files inside, but they are PNG images. I'm not sure how to use them; I thought they were animated files.
This is the option used in the demo, for sprite sheets, you need to enable animation (by adding a CanvasItemMaterial with the "particles_animation" property checked and the animation parameters configured, you should be able to find tutorials on this if you aren't familiar with it).
I could release a pre-configured example project, but in the meantime, I hope this helps.