We are planning to visit Norway in end of august(22-26 Aug). I am torn between two cities Tromso or Trondheim. I am interested to see Northern lights. I know its little too early for northern lights but in the last two years oslo have seen northen lights in late august giving us hope to see them this year if the conditions are good . which city has more possibility of witnessing northern light . tromso or Trondheim?