You don't have to live in the Phoenix area very long before you start hearing about snowbirds. Snowbirds aren't really birds at all.
Snowbirds are people who come to the Phoenix area and other parts of Sunbelt for part of the year to escape the harsh winters where they live. Snowbirds are typically retirees, and they have the freedom to be gone from their main place of residence for months at a time. They buy or rent homes, condos, or apartments in the Phoenix area. Snowbird season in the Phoenix area is usually from October or November through April or May. Then they pack up and head up north to home, where the summers are more tolerable.
Snowbirds are not to be confused with residents of the Phoenix area who are retired. They might have at one time been snowbirds, but they lose that designation when they move permanently to the Phoenix area. The same things that draw snowbirds in the winter make Phoenix a top-of-the-list permanent retirement area.
Some people don't like to be called snowbirds and take it as a derisive term. The phrase "winter visitor" is probably less offensive.
Snowbird Factoids and Things to Consider
During snowbird season, the population of the Phoenix area balloons, and the effects are noticeable.
When the snowbirds are in town, restaurants seem more crowded, especially during the early dinner hours.
In neighborhoods where there tend to be a lot of snowbirds, complaints about driving sometimes crop up. Snowbirds tend to be older and might drive slower.
Some younger people tend to complain during the winter about the preponderance of "white hairs" making the lines at Walmart longer, filling up the movie theaters, and buying up all the spring training baseball tickets. (Of course, they complain about all older adults, not just snowbirds.)
Phoenix-area golf courses love snowbirds, who take advantage of those weekday tee times. You can always find someone from Calgary or Minnesota on a golf course in the winter.
Snowbirds spend money in Phoenix, pay real estate taxes, shop, go to the theater and the symphony, and volunteer. Some of them may call Phoenix their primary home for tax purposes. Other make sure that they spend less than 180 days in Phoenix so their residency is not in question. Regardless, snowbirds add significantly to the economy of the region.
Some parts of the area are known for having a number of RV parks for snowbirds who choose that mode of transportation and living. East Mesa and Apache Junction have that reputation.
Long-term lodging is at a premium in the Phoenix area during the winter. If you are planning a trip to Phoenix and prefer a vacation rental to a hotel, you have a better chance of finding one between April and October when some snowbirds list their houses, condos, or apartments for rent while they are at their home in the North.