What Is Arizona's Climate Like?

Since the state of Arizona is rather widespread the climate conditions differ accordingly.
In some places the climate is typically desert-like with hot summers and cold winters.  The fall-spring temperatures are somewhere around 60° Fahrenheit while in the winter months i.e. November to February; they're somewhere around 40–75° Fahrenheit.

During the summer months, it does get quite dry and the temperature variations between night and day might vary very vastly. The part of Arizona which is a plateau enjoys a relatively cooler climate owing to its altitude. The other places in the state that are located at higher altitudes are also affected by the cold winds that come in from Canada. Rainfall in this country occurs twice; once in the months of July and August and the other during the winter. It is often accompanied by lightning and thunderstorms.

Arizona is a state that covers a large area and the elevations also vary from one place to another. In the lower elevations, the climate is most desert climate. The winter season in these regions is mild and the summers are hot. The average minimum weather is about 15 degrees Centigrade during the late fall to early spring months. The months from November to February experience temperatures ranging between four and 24 degrees Centigrade. The months between May and August experience a dry heat ranging between 32 and 48 degrees Centigrade. Occasional frosts are not uncommon in the winter months. The northern part of the state is a plateau with a relatively milder summer season, colder winters and cooler climates. Extremely cold temperatures (below minus 18 degrees Centigrade) are not uncommon. There are brought in by the cold air systems that come in from the northern states of the United States and Canada. The state receives an average of 322 millimetres of rainfall every year.    

The climate in Arizona is usually sunny hot with little to no humidity.  "Dry heat"  Occassionally they have rain and sand storms.  Average 90+ degree weather at present.  In months of June, July and August extremely hot with temperatures up to 115 degrees.  Best time to visit Arizona in my opinion is Fall/Winter months.

Arizona's climate is warm in some places in the places 350 days a year is sunny

Very hot and dry.