It may help, because lack of sunshine can reduce the rate at which ground dries out and also moss seems to need less sunshine than grass to thrive. However, it's not guaranteed that you'll have less moss. My lawn is full of moss after a long, cold wet winter, even though it's in full sun. Feeding a lawn so that grass grows strong and competes with the moss will help. Also forking the ground by hand or with a special machine will improve drainage so that the ground isn't so sodden all the time. The application of iron sulfate does help, and although it doesn't kill moss completely, it suppresses it for the summer.