So, our adventuresome Amelia is piloting a gas bag filled with lighter than air gas... probably helium, since hydrogen (al la Hindenberg) is dangerously flammable. Doing this in mid-winter is fool hardy, but Amelia has challenged the climate. So, she wants an area free of high winds, since the dirigible is notoriously hard to handle in even moderate winds. Additionally, the temperatures at her stopover point vary by nearly 60 degrees between day and night time. This, in the U.S. at least, would require, in my aviation experience, a city in a mountain valley with stable air and little wind, but one that cools dramatically after sunset. I can think of a couple of candidates...Missoula, Montana for one, with Boise, Idaho a close second, with Jackson Hole, Wyoming also a consideration. Any farther west than that and the temperature do not fluctuate that dramatically. Calgary, Alberta, in Canada also comes to mind...