The weather is warming up. And so is the housing market, especially in the core of Greater Boston.

Home sales in Massachusetts shot up 31 percent in March over last year, according to data out Tuesday from the Warren Group, while condominium sales climbed 27 percent. Real estate agents and other specialists said they expect that pace to keep up through the key spring selling season.

And for one of the few times on record, condos are out-pricing single-family homes, a sign of strong demand to live in Boston and its immediate environs.

A bit of that year-over-year surge reflects a rebound from last winter, when snow and cold kept buyers home. But mostly, real estate observers say, it reflects a market that is very strong this spring, in certain places.

“It’s hyperlocal,’’ said Linda O’Koniewski, the chief executive of RE/MAX Leading Edge in Boston. “Inside [Route] 128, in the more desirable school systems and the sweet spots in price, it’s at an insane pitch.’’

That — combined with still-tight supply — is sparking bidding wars and giving sellers their pick of strong offers.

And buyers are learning they need to jump, said Eileen Lorway, a Redfin real estate agent on the North Shore. In strong pockets of the market, she said, it’s pretty common these days for a house to be listed on a Thursday, host open houses over the weekend, and be under contract by Tuesday morning.

“It’s become a very fast market,’’ she said. “Sellers have the confidence to set an offer deadline. That says something.’’

The strongest markets, said Warren Group CEO Tim Warren, are the places you’d expect: suburbs that have added well-paying professional jobs, such as Watertown and Needham, resurgent city neighborhoods such as Charlestown and South Boston, and places like downtown Boston and Cambridge that appeal to empty-nest baby boomers and international investors.

That’s helping new high-end developments like Pierce Boston in the Fenway, which launched sales earlier this year. So far, prices are running 20 to 30 percent higher than developers originally planned, said Sue Hawkes, the project’s marketing consultant. Many of the buyers plan to move in from the suburbs.

“These people are leaving suburban, single-family homes,’’ she said. “We’re in the midst of a very real paradigm shift.’’

But not every place is seeing the boom. Of the 295 cities, towns, and Boston neighborhoods that Warren tracks, only 84 have seen their median single-family home prices recover to 2005 levels.

The rest are still below last decade’s peak, with some in Worcester County down by as much as 30 percent.

And statewide, prices are relatively stable. Condo prices — helped along by a surge of luxury units sold in Boston — climbed 10 percent, compared to last March, to a median of $320,000. But the median price of single-family homes, which make up a much larger chunk of the market, actually fell nine-tenths of a percent, to $315,000.

But those broad numbers are masking a market that’s intense in certain places, and that — despite historically low interest rates — is tough on first-time buyers and others trying to find an affordable place to call home.

“Entry-level and mid-market buyers — typically the housing market’s bread and butter — are likely to face stiff competition, rapidly rising prices, and very limited inventory,’’ said Svenja Gudell, the chief economist at the real estate website Zillow.

“The patience of many buyers will be tested in coming months.’’

Tim Logan can be reached at tim.logan@globe.com. Follow him on Twitter at @bytimlogan. Sacha Pfeiffer can be reached at pfeiffer@globe.com. Follow her on Twitter at @SachaPfeiffer.