The Southwestern region includes the states of Arizona, California, Colorado, Nevada, New Mexico and Utah. January is a cool to mild month with most areas remaining very dry. The wettest areas can be found along the California coast.
Elevation is important as well.
The higher you go, the colder and snowier it gets. It is cooler along the coast because the air blowing off the Pacific Ocean is cooler. There is very little rain, but most of the rain falls in the mountains during thunderstorms. The hottest recorded temperature in the Southwestern region is 134 degrees Fahrenheit in Greenland Ranch, California on July 10, 1913. The coldest recorded temperature is -69 degrees Fahrenheit in Peter's Sink, Utah on February 1, 1985.