House prices in major local markets posted monthly gains stronger than seasonally expected. "The larger-than-average increase in home prices from April to May 2009 could indicate that seasonal price fluctuations do not fully account for the strength we are seeing in many areas and that seasonal gains are being augmented by a more general recovery in the housing market," Radar Logic says in its RPX monthly housing market report. Of 25 major metropolitan statistical areas (MSAs) tracked by Radar Logic, 22 -- or 88% -- posted month-over-month price gains in May. The 25-MSA composite reading rose 3.7% overall since late March, when it hit its lowest point since the beginning of the housing crisis. Prices in the Western region performed "particularly well," rising 6.9% since their low in late January. "We have been observing strength in the RPX since April, and it now appears that this improvement in home prices was an early indicator of some strength in the general economy," Radar Logic says. The strongest monthly gains in price per square foot -- the scale Radar Logic uses to eliminate the exaggerating effects of house size and location -- occurred in the San Francisco (7.3%) and Minneapolis (5.5%) MSAs. The Milwaukee MSA followed with a 4.9% increase, while Charlotte and San Jose both gained 4.7%. Only Atlanta, Las Vegas and New York took exception with the broader trend, posting monthly declines of 0.2%, 0.6% and 1.7%, respectively. Radar Logic attributed the price declines in Las Vegas and New York to the strong economic ties to struggling tourism and finance markets in those MSAs. Write to Diana Golobay.