On Thursday, Holland & Knight will once again play host to the “Rooftop Deck Caucus,” the informal nickname for the throng of fun-seeking congressional staffers who flood the lobbying firm’s sun-splashed offices each summer.  

Public policy head Rich Gold — “and DJ,” he added — told HOH the come-as-you-are gathering (800 17th St. NW) began as an in-house shindig, but noted that it has since evolved into a widely attended opportunity to blow off some steam.  

“It’s kind of a tongue-in-cheek event, to say the least,” he suggested. “It also tends to get hot and sweaty, given Washington in July.”  

Skyrocketing temperatures or not, Gold said he’s noticed some crossover between the more member-friendly reception his group puts on in the Cannon Caucus Room and the open-air soiree — overlooking the White House, no less — happening this week.  

“It has started to get out,” he said, estimating that around a dozen intrepid lawmakers have begun routinely mixing with the 300-odd partygoers that congregate on the roof each year.  

Those willing to brave the humidity for this year’s 8th annual outing, which is scheduled to take place from 6 p.m. to 9 p.m., are set to be rewarded with spirited “cocktail ice creams” and “adult” sno-cones, Baja-style fish tacos, mini crab cakes, the musical stylings of the Grateful Dead and Jimmy Buffett and “maybe even a photo booth.”  

“Come party till you pass out. Something Washington doesn’t do nearly enough of,” Gold counseled.