The New York Times runs a whole article about itinerant rich people:
Oren Alexander, the Miami-based real estate agent to the rich, no longer thinks of his clients as second-home buyers. Today's ultrawealthy, he says, are often looking for "the four-pack" — a pied-à-terre in New York, a beach house in the Hamptons, a ski villa in Aspen and a winter condo in Miami.
"They're not really looking for full-time residences anymore," said Mr. Alexander, a broker with Douglas Elliman. "They want stops on the big circuit."
New York's peak millionaire population is in June, when the city is home to 32,500 people worth $10 million or more. In February, the low month, the population of deca-millionaires plunges by nearly two-thirds, to 11,700.
... Los Angeles may have consistently sunny weather, but its wealthy population is volatile, rising to 11,170 in June and falling to 5,630 in February, when many of its rich head to mountain ski resorts or tropical locales.
No mention at all in the article of newly high marginal income tax rates — above 50% in both Los Angeles and New York City when you add together federal, state, and local taxes — and how they might motivate rich people to spend enough time away to avoid being a full-time resident for tax purposes.