The months from June to August are considered the off-season for Las Vegas. These are the off seasons because the daytime experiences very high temperatures ranging from 90-100s. If you are okay with the hot and humid climate, then this can be the best time of the year to visit Las Vegas. From late June through August, accommodation rates are very low and the city experiences a low rush during this time of the year. So, if you want to save your expenses and want to know what is the best and cheapest month to fly to Las Vegas, then months from June to August will be your best bet!