It’s the winter of golf in Massachusetts and just about everywhere else, thanks to an explosion of golf simulators, both in homes and in retail establishments such as Harbor 9, which are popping up everywhere. On top of that, there’s a brand new professional simulator league on ESPN, the TGL, that features some of the game’s biggest stars, such as Tiger Woods and Rory McIlroy.

In Massachusetts, where golfers have long had to hop on a flight to Florida or Arizona to get a winter golf fix, the rise of the indoor game has transformed the sport. And the rise of the simulator — a computer system that tracks a shot hit into a screen or net and then projects it onto a virtual course, mimicking the flight path an outdoor shot would take — has coincided with an overall explosion in golf, which has boomed in popularity since COVID.

“As a seasonal state, simulators provide an opportunity to keep a club in your hands year-round, and that has dramatically improved the number of people playing golf, and their level of play,” said Jesse Menachem, executive director of Mass Golf, the 125-year-old nonprofit that saw its membership jump from 85,000 before the pandemic to 133,000 last year, though that’s just a fraction of the estimated 500,000 to 600,000 golfers in the states.

While the initial burst was attributed to the fact that the outdoor game provided a socially distant way for friends to get together, Menachem said, much of the continued acceleration comes from the stress-free entry that indoor simulators provide for newcomers.

“Golf can be extremely intimidating, but the indoor game offers this easy way to try out the game with some privacy, without that feeling of standing on the first tee box with a bunch of old guys standing there watching you,” said David Huddleston, the owner of Harbor 9. “We have so many women who have picked up the game after coming here, because even at a driving range it can feel intimidating with the person next to you watching you whiff on your first swing.”

Harbor 9, like many of the estimated 75 retail simulator places in the state, offers a full-service bar with pub food, providing an atmosphere that is as much about socializing as golf. Most simulator places charge in the range of $40 to $75 to rent a bay for an hour, depending on the time or day, and that cost covers four golfers.

“We have people who are in here because they’re serious about golf and want to play in leagues, and then we have people who just want to hang out with their friends and have a beer and smack the ball around,” said Joe Shea, the owner of Birdie Bar in Waltham, which has been so successful since it opened two years ago that he’s opening a second branch in Burlington this year.

“African-Americans and juniors are the two biggest growth groups in golf right now, and it’s places like this that are making it more accessible to get into the game,” Shea added.

According to the latest figures from the National Golf Foundation, 6.2 million Americans hit balls on indoor simulators in 2023, a 72 percent increase since before the pandemic, and a number that is expected to grow significantly when 2024 figures are released.

In total, 32.9 million people played some form of golf in 2023, a number that includes the increasingly popular interactive driving ranges such as Top Golf, which opened a Canton location in 2023. That’s a 41 percent increase since 2019.

And now, the professionals have come indoors. On Jan. 7, ESPN aired the first match of the TGL, an indoor league that takes place on a simulator the size of an IMAX screen, inside a purpose-built arena in Florida that features a massive putting green, bunkers, and all sorts of technological doodads.

“It’s not traditional golf,” Woods said on the broadcast, “but it is golf.”

Like Woods, many of the biggest PGA stars are competing, divided into six teams that are loosely affiliated with a city. Boston Common Golf — which features McIlroy, Adam Scott, Hideki Matsuyama, and Vermont’s Keegan Bradley — is owned by Fenway Sports Group, whose principal owner, John Henry, owns The Boston Globe.

Whether the simulator craze endures remains to be seen, said Gary Larrabee, a 75-year-old golf historian from Wenham who has seen many fads come and go in the game.

“There’s always been golfers who want an opportunity to swing the club in the winter, even if that’s into a net in the basement,” he said. “But with professionals like Tiger Woods involved, and with all these simulator places opening up, there’s no denying that it is the big thing right now.”

At-home golf simulators, which can cost anywhere from $5,000 to $50,000, have become the centerpiece of many dream “man caves,” offering golfers the chance to not only sharpen their skills but also to virtually play many of the world’s most famous courses. And with the outdoor game so popular — it’s now categorized as “green-grass golf” — tee times have become hard to come by, so 18 on a computer is often the only option on a busy weekend.

But simulators provide something the outdoor game does not, something golfers love: data. With each shot, the computers spit out mountains of information on things like club head speed, ball speed, spin rate, and launch angle.

“Golf people are nerds,” said Jamie Cahill, a self-described golf junkie from Scituate, who was about to play a “quick 18″ at iGolf in Pembroke. “They love technology, they love tinkering with the gear, and we love the feedback of the instant data you get on a simulator, where you can figure out how open or closed your club face is on impact, so you can be, like, ‘Oh, that’s why I’m slicing the ball.’”

Still, the simulator game, just as the one played at country clubs, is as much about golf as it is about golfing — that social activity, done in a foursome, designed for three people to laugh at the other. Women’s leagues have become popular, as have after-school programs and even birthday parties. Many simulators have arcade-style options such as allowing players to hit balls into a junkyard, or even to kick soccer balls at the screen.

But the core of the golf simulator boom remains golf guys, and at the men’s league night at Harbor 9, the room was buzzing with the sounds of drivers smashing balls, of chops being busted, of beers being ordered. All of it centered around this new version of a very old game, and the simple pleasure of hitting a ball with a stick and then screaming at it to get in the hole.

Billy Baker can be reached at billy.baker@globe.com. Follow him on Instagram @billy_baker.