It’s difficult to say when the best time to visit Las Vegas is since it's perennially peak season in the city that never sleeps. While the cooler climes of spring and fall make the stay that much more pleasant, summer Las Vegas weather brings the kids and the TMZ-style pool parties. New Year’s Eve, Valentine’s Day, Memorial Day weekend, Labor Day weekend and July 4th attract the super crowds. Lines are long, rooms are expensive and service just that much more challenging. If you are deciding when to go to Las Vegas you might want to avoid the “citywides” — enormous conventions such as the International Consumer Electronics Show, MAGIC and National Association of Broadcasters that rain suits on the city, jam its cellphone circuits, drench it with expense account money and drive up room prices. If you're planning on getting out of the city, spring and fall are the best time to visit Las Vegas and the Grand Canyon - a popular side trip combination.
Las Vegas's weather during the winter season, which ranges from December through mid-February, brings chilly temperatures and rain. A classic low season period comes between Thanksgiving and New Year’s Eve. This is the cheapest time to visit Las Vegas and is when you will find the comfortable traffic levels, easy lines and loads of 2-fers and discounts.
Las Vegas is popular all year, so there isn't much of a shoulder season. If there is such a thing, it happens somewhat in the summer when high temperatures make people think twice about taking the drive—the drive and ground transportation market accounts for about two thirds of the visitor volume.