Data from Realtor.com shows this September to be unlike Septembers of past in regards to real estate. According to the website, a preliminary review of the data shows that September could be the beginning of “the hottest fall in a decade.”

Traditionally, fall is the time of year when real estate markets tend to slow. This fall, however, markets are heating up.

“The fundamental trends we have been seeing all year remain solidly in place as we enter the slower time of the year,” Realtor.com’s chief economist Jonathan Smoke said in “The Hottest Real Estate Markets for September 2016.”

“That means short supply and high demand, which results in high prices,” he said.

According to the website, Realtor.com’s economic data team considered the number of days homes spent on the market (a measure of supply) and the number of views listings on the site received (a measure of demand) to compile its list of the hottest markets for September.

With 10 markets — including San Francisco (no.1); Vallejo (no. 2); San Diego (no. 5); Stockton (no. 6) and San Jose (no.9) among the top 10 — California had the most cities in the top 20. Other states with multiple markets on the list included Texas (Waco, no. 10 and Dallas, no. 4); Colorado (Denver, no.3 and Colorado Springs, no. 16); and Michigan (Detroit, no. 14 and Grand Rapids, no. 20). Rounding out the list were markets in Indiana (Fort Wayne, #7); Ohio (Columbus, #12); Washington (Kennewick, #18); and Tennessee (Nashville, #19).

Bankrate.com also reported on a couple of fall trends in a recent article.

According to “Fall housing trends: What will happen to home prices and mortgage rates?” two factors are dominating real estate this season: There aren’t enough affordable homes for sale to satisfy demand in a many housing markets and mortgage rates remain close to near historical lows.

“The result is frustration,” the article reported. “Low mortgage rates boost affordability, but prospective buyers feel like they don’t have much choice.”