As much as the temps vary, for the most part you USUALLY will not need a fan at that time of year. Of course, that depends on where you are coming from! When my parents arrived mid-December it was in low 70s and I was in jeans and long sleeves and Dad broke out his shorts, Mum was in her skirt. The very next week it got cold (but not as cold as they had it in Scotland) and we started these night time frosts etc. Of course, I personally thought it to be terribly cold but I live here now! Layers are your best bet anyway, but pants and t-shirts with a long sleeve sweatshirt/jacket will likely suffice for the early mornings/late evenings. If the sun is NOT out it can feel colder and vice versa.