Phoenix does not experience tornadoes every year, nor does any city. Since official records began in 1950 Phoenix and its suburbs have experienced about 35 tornadoes, most of them weak, making for an average of about one tornado every two years.
Tornadoes can happen on any day in any month. However, general times within a month may see more or fewer tornadoes on average depending on the month. For example usually more tornadoes happen in late March than in early March.