PORTSMOUTH — As June arrives — traditionally the strongest month of the year for real estate closings — sales of Seacoast Region single-family homes set records in May with 99 total transactions among homes and condominiums.

Sales of traditional single-family homes were the highest since June 2011.

According to the Seacoast Board of Realtors, the surge in sales was up 26 percent from last year and 83 percent from April.

Condo sales notched 51 transactions — the biggest month in condo sales since the board began tracking the 13 Seacoast towns in 2009.

May represented the strongest performance of the year in all price points except the $600,000-to-$1 million range, where there was one recorded transaction, matching January's total.

Every price category represented a new high for the year, the board said, with 69 sales of homes priced under $400,000, nearly doubling last month's total of 39.

Condo sales are up 70 percent from a year ago and 59 percent from last month.

In all, total sales of single family residences are ahead of last year by 12.8 percent and condos are enjoying a 30.1 percent resurgence from 2011, the board said in a news release.

Lauren Kane, president of the Seacoast Board of Realtors, said the spring-summer season represents a particularly strong opportunity to invest in the real estate market, “with unbelievably low interest rates, affordable prices and plentiful inventory.”