May proved to be a strong month for nationwide and Bay Area home sales, according to data from Realtor.com. Vallejo-Fairfield took the crown for being the hottest market in the country. The S.F.-Oakland-Hayward region achieved a “hotness rating” of 2 this month with properties staying on the market for 24 days.

Realtor.com chief economist Jonathan Smoke says the momentum shows no signs of slowing. “Based on our early read of demand and supply data in May, this spring’s real estate market is coming in strong, just as we expected,” he says, adding demand and low mortgage rates are driving buyers into the market.

California continues to dominate the rankings, taking seven out of 10 top slots.

While the Bay Area continues to lead the nation, several worrying signs have started to emerge in recent months that could signal a wider downturn in housing. Silicon Valley luxury homes, for example, have started to see a slowdown.