Not a silly question at all, particularly if you are worried about possible side effects from installing a mod :)
I play vanilla so I can't comment on mods. I generally set my game to a week of Spring, Summer, Autumn and Winter. During the Spring and Summer seasons it seems to rain every other day which is disappointing. I live in Britain where the summer weather is usually very cold and wet so I really want lots of summer sunshine for my sims. I think you just got very lucky or rather your sims did, having two weeks of sunshine :)