Asking prices of homes listed for sale on real estate portal Trulia.com in January were up from a year ago in 86 of the 100 largest U.S. metros, according to a monthly report released today.

The report, which covers roughly 4.5 million for-sale and for-rent properties listed on Trulia through Jan. 31, showed asking prices up 5.9 percent from a year ago, and growing by a seasonally adjusted 0.9 percent from December to January — the biggest month-over-month gain since March 2012. 

In some markets, the strong growth in asking prices doesn’t necessarily indicate that worries are over, said Jed Kolko, Trulia’s chief economist.

“In many local markets today, dramatic price gains can mask serious red flags,” Kolko said in a blog post. “Strong job growth, low vacancy rate, and low foreclosure inventory — not huge price gains — are signs of a healthy housing market.”

Trulia identified San Francisco, San Jose, Seattle, Denver and Salt Lake city as “booming” markets with strong fundamentals.