The summer real estate season — long perceived as a relaxed time marked by beach-bound brokers, holding-off-until-fall sellers, and leftover spring properties — is undergoing a shift as agents court more serious buyers and sellers profit from decreased competition.

While brokers often shift open houses to weekday evenings and fewer units generally go on the market, experts say the snail’s pace summer real estate season is a thing of the past.

“Traditionally, everybody places their properties on the market in September or over the springtime because those historically had been the best selling times,” an executive vice president at Prudential Douglas Elliman, Jacky Teplitzky, said. “But that trend has changed. I don’t think the real estate market is so seasonal any longer.”

Summer sales, according to the president of the real estate appraisal firm Miller Samuel, Jonathan Miller, tend to reflect the previous spring, with a busier spring season leading to a relatively busy summer.

“It would appear to be, based on spring activity, a pretty active summer,” Mr. Miller said, adding that it would not likely reach the record transaction activity of the first quarter. “After six months have passed, some of the momentum and influence of bonus money weakens.”

With inventory levels being 25% lower than they were at this time last year, he said, there will be fewer excess listings than at this time in 2006, which could translate into higher prices.

Rather than seasonality, Mr. Miller said the market over the past two years has been more sensitive to mortgage rates and other factors. “There is not the same degree of disparity between peaks and troughs,” he said.

While some brokers advise sellers not to put apartments up for sale in summer, the ones who decide to sell, especially amid low inventory levels, contend less with competition from other sellers and, as a result, their apartments get more attention.

Summer is a popular time for parents buying for children, for foreign buyers, and for those simply in dire need of shelter. But even for properties that aren’t known for summer deals, such as the grand family apartment, Ms. Teplitzky said, the Classic Six seller who bucks this trend benefits from easier showings because buyers are limited to fewer such units.

Experts say new development continually is being added to the housing stock during the summer months. “When a new development comes online, someone isn’t going to say, ‘I really want this location and this building, but I’m going to wait until after October to buy anything,” Mr. Miller said, adding that there’s a risk in waiting on projects that are moving quickly.

For brokers, the months of June, July, and August can be a time for hunting down new exclusives and working referrals.

“I walk to my beach and talk to somebody and they talk to somebody else and before you know it, you hear that this one’s mother died and the estate needs to sell the apartment,” an associate broker at Bellmarc Realty, Lewis Friedman said. He said he summers at Main Beach in East Hampton and gets more customers in the summer than throughout the entire winter.

Mr. Friedman continued: “It’s much easier on the weekends and in the summer to meet with people find out what’s going on. If you’re in the city, things are so much busier and you never have time to talk to anyone.”

Others are wary of taking time off. “I always have a debate with myself if I want to go away over whether there is a right time and anytime I say, ‘This week is going to be slow,’ when I go away, my phone is ringing off the hook,” Ms. Teplitzky said.