Fall: September - November
In September, the weather begins to shift and the days start getting shorter. Daytime highs hover around 50°F but often feel even cooler with the winds and more frequent rainfall. Some attractions start to close down in late September, but it's usually easier to book accommodations as there are fewer tourists. You might be able to see the northern lights towards the end of the fall, but if this is something you want to experience you are better off visiting in the winter months.