If you are planning to travel to Las Vegas, you have the added benefit of Las Vegas being an almost entirely year-round vacation destination. There are very few times when traveling to Las Vegas would not be a good idea. The first three weeks in December and the weekdays in July are the worst times to travel to Las Vegas.
However, any other time that you travel to Las Vegas you will find the city bustling with activity. The most packed times to visit Las Vegas is on the weekends, the Super Bowl, Valentine's Day, Presidents' Day, the Final Four, Easter, Cinco de Mayo, Memorial Day, July Fourth, and Labor Day. Even busier than these days is the week between Christmas and New Year's.
You should also be aware that if you travel to Las Vegas when any of the fifty or more conventions occurs, during which time ten thousand or more participants arrive, you would probably find a lack of availability and higher prices. Any time you go during a sporting event, you should also expect large crowds.
During a time with no conventions, holidays or sporting events you will typically find that the Sunday through Thursday time has small crowds, cheaper prices and a more relaxed atmosphere.
In terms of weather, it is best to visit Las Vegas in the spring and fall. From March to May the daytime temperatures are at least seventy degrees or higher. During the summer months you will find temperatures during the day starting at, at least one hundred and ten in the shade.