The last day of August added yet another unwanted record to Washington weather statistics when yesterday's high temperature of 95 degrees established the month as the hottest here ever.

The mercury's now almost routine daily surge past 90 degrees came at 1 p.m. and with it the record for the all-time insufferable month, set previously in -- you guessed it -- July.

"We've got the record, there's no doubt about it, it's just a question of by how much we're going to break it," said National Weather Service forecaster Harold Hess, who has been delivering the bad news to Washington through most of the summer.

Though the final figures had not been tallied yet, Hess predicted that yesterday's temperature would break the previous highest average monthly temperature of 95 degrees should help topple July's record for highest average monthly temperature by about one degree, Hess said.

As legions of sweat-soaked Washingtonians already know, this was a summer of records. Century-old highs for daily temperatures fell by the wayside on Aug. 8 and 11, when the temperature crept past 100. Even more memorable was July 16, when the 103-degree tempreature, the record for the day, caused summer school sessions to close, construction workers to put down there tools, and some municipal employees to throw down their pencils and go home.

A history-making 21-day heat wave finally ended on Aug. 14, marking the longest stretch of tempreatures of 90 or above since 1972. Seven of those 21 days fell in July, crowning it the king of hot Julys.

To top it all off, August was one of the driest months on record, with the Washington skies producing only 1.11 inches of rain, compared with a normal average of 4.67 inches for the month.

On the bright side, Counin of Government officials issued only one air polution health advisory notice this summer, this weekend when pollution reached unhealthy levels especially for people suffering from cronic respiratory allments. As to the big question of why it has been so hot, officials aren't sure.

"What has happened is that large-scale circulation patterns in the atmosphere have prevented any cool air masses from Canada from reaching Washington," said Hess. "Why that happens, I'm not sure anyone could tell you. What makes it more uncomfortable, however, is the sunshine, the high humidity, and on most days we haven't had much of a breeze. But actually," he said, "the main thing is that people are just fed up with it."

Meanwhile, on the Mall, hordes of people enjoyed the last gasps of summer, seemingly oblivious to the history-in-the-making heat. Professional frisbee player Harvey Brandt limbered up to await his chance to show off in the fourth annual Smithsonian Frisbee Festival. "Actually, this isn't much of a holiday for me," he said. "Practice starts Tuesday for the Ultimate Frisbee team at Cornell."

National Gallery Guard Reginald Payne counted the heavy traffic at the last day of the Post-impressionism exhibit in the East Building. "I don't mind working a holiday, since it's cool in here," he said, clicking off another of the building's 26,000 visitors yesterday. "but I hope I won't be here," he sighed, fanning his sweating face with his hand.

And tourist Jim Bierma just suntanned on a bench on the mall, enjoying the last free days before his return to graduate school. "Really I don't mind going back," he said, tilting his head back toward the sun. "I've done summer, I'm looking forward to doing something else."