When people who are not familiar with the weather in the southwestern United States plan trips to national parks, one of the biggest questions that they will have is “what is the weather going to be like?” Naturally it is not possible to predict exactly the temperatures on the day you will be traveling, but many times if they are leaving from Las Vegas for the trip they will potentially rethink their choices if they see how hot it is in the city during the summertime. What is important to understand about the southwestern US is that the temperatures can have wide variations on the same days due to the topography of the areas that you are comparing. The temperatures that you are experiencing in Las Vegas on the day of the trip may not be the same temperatures you can expect when you get to the destination, depending on the time of year. It is always best to look at weather predictions a few days in advance for the area that you wil be traveling to in order to get a better idea of the weather you will be dealing with.
Zion is quite different than Las Vegas, and as a result will have very different temperatures. Generally, you will see somewhere between a 10 to 20 degree temperature difference between the two, with the summer temperatures in Las Vegas going higher while the temperatures in Zion remain more consistent. When you look at the temperatures on Las Vegas on a typical summer day that is 104 degrees, you will probably be seeing temperatures in Zion on that same day of about 85 degrees. At night on that same day you will probably be seeing the temperature drop to about 65 or 70 degrees. This is due to the fact that Zion is different than Las Vegas as far as topography, and heat tends to not get trapped in the area the same way that it does in the city. On excessively hot days in Las Vegas where the temperatures at night do not go down much further than 100 degrees, you can easily see Zion temperatures dropping to around 60 or below. For this reason, it is best to plan for both hot and cold temperatures in Zion if you will be staying overnight as well as hiking during the day.
Zion Canyon is almost always perfect weather for hiking, with temperatures in the summer being in the high eighties and in the winter being in the high fifties. The idea hiking weather is actually not going to be too warm, as your body is going to make heat while you are moving. For this reason, it is not necessarily best to use the actual temperatures as a gauge for comfortable weather, as many people not from the area will misunderstand what kind of temperature is comfortable for being outside. Overall, Zion is going to give you nearly perfect weather all year long, and in the summer can actually be a reprieve from the Vegas heat.