Victor Martinez, 40, of Silver Spring, swings high in a hammock in Wheaton Regional Park. (Family Photo)

It’s not often in Washington sports that people like things. Just. The way. They are.

But even for fans jaded by the recent mediocrity of the region’s pro-sport offerings, and bracing for the forecast arrival of temperatures near 90 on Monday, a glorious spring Sunday at Nationals Park proved surprisingly close to . . . perfect.

“Could we just bottle this weather and have it at every home game this year?” Nationals announcer Dave Jageler beseeched Sunday afternoon, his voice echoing throughout the concourses, restrooms and box seats of a nearly full stadium on South Capitol Street.

“And could we freeze the standings, too?” answered a man in a No. 37 Stephen Strasburg jersey waiting in the Flippin’ Pizza line. “I kinda like first place.”

It was a perfect day for many things in Washington: lawn mowing and car washing, bike riding and park sitting. It was an April idyll just right for filling sidewalk tables from H Street to Wisconsin Avenue and dashing through fountains in Silver Spring or Georgetown. The checkout line in the garden center at the Hyattsville Home Depot was a dozen people long by 9 a.m.

In Springdale, the Jackson family was inspired by the weather to walk off a chicken and shrimp dinner with a hike from their home to Wegmans — 1.3 miles away in Glenarden — and back.

“This is something we’ve wanted to do for some time, and because it is so glorious out, we decided this was a good day to start,” said Maria Jackson, 46, an insurance company government affairs director, walking with her husband, Eduardo, and twins Langston and Logan, 8.

Scott Scheurer, 24, was sitting outside of Northside Social, a restaurant in Arlington County, watching the Wilson Boulevard traffic go by and completing his to-do list for the day: “Sitting out here enjoying a big glass of wine . . . and being out of the house.”

But for the 25,679 people at the Nationals’ game, it was a day to blink as much in disbelief at the baseball team’s recent performance as at the brilliant sun. The sky was blue, the humidity was low, and the Nats were alone atop the National League East standings, a single game short of the best record in the majors.

By Sunday’s opening pitch, they had already clinched the four-game series with the Cincinnati Reds, their third series win in a row.

“This doesn’t even seem like D.C., does it?,” said Vince Tur-Rojas, standing at the rail behind Section 116 with a box of chicken fingers in one hand and a can of beer in the other.

He was still buzzing from the night before, when the Nats won their fifth game in row — in a complete-game, two-hitter by pitcher Edwin Jackson no less — and the Washington Capitals beat the Boston Bruins to even the Stanley Cup conference quarterfinals.

“This is about as good as it. . . . Yeah! Go! Go!” Tur-Rojas interrupted himself, risking spilling his beer, to cheer for a two-run double by first baseman Adam LaRoche.

The Nats got off to a bad start Sunday, giving up a grand slam in the first inning. But by the seventh, they had battled back to a tie and guaranteed a day that was breezy, mild and thrilling.

The early success of the Nationals has run counter to the general trend among professional teams in Washington, where fans have learned to enjoy a brilliant day at the stadium in spite of the action on the field. The Redskins have tainted many a crisp fall afternoon with an ongoing run of mediocrity and no trips to the Super Bowl in two decades. The Wizards, meanwhile, have a 14-46 record.

And the Nats? They’ve never looked this promising. Since the Montreal Expos franchise moved to Washington in 2005, the team has never won more games than it lost. The Nats came close to that milestone twice, in the inaugural season, when the team finished 81-81, and last year, when it went 80-81 (one rained-out game was never played). In five of those seven years, the Nats finished in the division basement.

The fast start comes with a big asterisk: The baseball season is very long, and April results can be misleading. Overall, the Nationals haven’t hit very well, which most observers would consider to be a weakness in a game involving a bat and a ball.

But the starting pitching has been, for the most part, spectacular. Before Sunday, Nats pitchers had allowed just 17 earned runs this season, for a collective earned-run average of 1.82 per nine innings, best in baseball. Super­star Strasburg, who spent most of last year healing from elbow surgery, has given up just one earned run in his first two games. He is to pitch again Monday.

“I think you have to go back to the days of [Hall of Fame Senators ace] Walter Johnson to find pitching anywhere close to what they have now,” MASN commentator and Washington baseball historian Phil Wood said as he basked in the sun on the left field concourse Sunday. “We’re still looking at a small sample size [of games played], but it’s hard not to get a little bit amped up about this team.”

But for many of the fans on hand, the prospects of a winning season or even — don’t jinx it — more were joys to be ranked somewhere behind the exquisite pleasantness of this particular game on this particular fantastic mid-April afternoon. The seats, crowded to the very top rows, were full of sun hats and hot dogs, spaghetti straps and Italian sausages. Kids, many of them still wired from spring break, wore themselves out on the packed jungle gym behind left field.

“I’m wondering why I spent $30 for tickets when we’ve been sitting here all day,” said Joe Howell, lounging with his wife, Cher, on one of the sofas arranged under sun sails behind the Scoreboard Pavilion and watching the action on a jumbo TV screen. The two recent transplants from Boca Raton, Fla., said they were doing yardwork Saturday in Burke when the Nats radio play-by-play convinced them to come out for a game.

“When you live and work in Washington, you spend all of your week in traffic or in buildings,” Howell said, his sunglasses reflecting the snapping flags over center field. “Whether they win or not, this is just great.”

On Sunday, they didn’t: The Reds won a nail-biter in the 11th inning. It was the third extra-innings game in four home games this season.

And for about 25,000 fans, after a great game on a day full of sunshine and promise, that may not have mattered much at all.

Staff writers Jeremy Borden and Avis Thomas-Lester contributed to this report.