The hottest times of the year are from May until September when the temperatures are between 89° F and can reach up to 102° F, if not higher. Sightseeing in these temperatures is doable, but one should take precautions and this time of the year will also be popular. This city is always a popular place, so there aren't really any times of the year when you will get a good deal on a hotel, but look around and you might fight something. However, if you want to pay less you should look at hotels that aren't close to the strip because they are relatively cheaper.
The best times to visit the city are between October and April, during these times you will experience temperatures ranging from 66° F up to 81° F. This is the best temperatures for visiting, however, because of the holidays it is also one of the busiest times to visit.