SEATTLE—Accelerated mutifamily rent appreciation in the obvious hot spots, such as New York City and the Bay Area, is hardly news by now. But now rents are rising in smaller markets, with some—including Denver, Kansas City, MO and Portland, OR—seeing annual growth at more than twice the national average, according to the Zillow Group.

Data from Zillow show that the usual suspects—including Boston, Los Angeles and Zillow's hometown of Seattle as well as New York and San Francisco—have continued to see rents increase at a faster pace year-over-year than the national average of 3.3%. Likewise for the Texas boomtowns of Dallas, Houston and Austin. However, markets that saw flat growth or even declines two years ago, such as St. Louis, are now catching up.

Meanwhile, Y-O-Y increases in pricing on for-sale homes has slowed for nine consecutive months, with January representing a 5.4% increase from a year ago. Home prices' 0.2% increase from the previous month was half the rate of the month-over-month gain in rents, according to Zillow. The median rent across the US is now $1,350 per month, and Zillow expects rent growth nationwide to surpass growth in home sales by year's end.