The number of single-family homes and condominiums put under agreement was up again in August, the 16th straight month of year-over-year increases, the Massachusetts Association of Realtors said Tuesday.

The number of Bay State single-family homes put under agreement in August was up 27.87 percent versus the same time last year, the association said, and the number of condos put under agreement in August was up 30.73 percent.

The association’s pending sales analysis counts homes that have been put under agreement but are not yet completed sales. Often six weeks can elapse between the time a home is put under agreement and the time that the sale closes. In general, economists look at closed home sales when they seek to evaluate the condition of the market, but those data points can be several weeks old. According to the association, pending sales can sometimes give more of a real-time indication of where the housing market might be heading.

“Summer may be a time to take vacations, but this year also was time for buyers to get into the market and purchase homes,” association president Trisha McCarthy said in a statement. “August pending sales numbers confirm the continued high level of activity that Realtor-members are seeing and feeling in the market. This bodes well for strong closed sales results in the fall and early winter.”

The last month for which hard sales data is available is July. Two weeks ago, the Warren Group reported that July sales for single-family homes in Massachusetts rose nearly 27 percent because of increased confidence in the local housing market and continued low interest rates. It was the best July for home sales in Massachusetts since the market’s peak in 2005, said the Warren Group, a Boston firm that tracks local real estate activity.