yup it is JAskyday1
i have solved the problem, sort of, by copying the file sky_semisun7 and renaming it JAskyday1. The sky works very well in the Fern Bay environment and imo looks alot more intresting than just a plain blue sky.
Rather intrestingly, if you remove the JAskyday1 file totally, the game doesnt load a sky and defaults to a light grey colour, which actually also works extremely well as an overcast sky. Try it!