(CNN) The searing heat sometimes makes players hallucinate, the night sessions often go into the early morning hours -- and one tennis superstar calls it the "Happy Slam."

Staged near the center of Melbourne's buzzing downtown, the season-opening Australian Open is unlike any of the sport's other three majors.

Starting Monday, fans will see top players like Roger Federer, Serena Williams and Rafael Nadal hit the comeback trail, while Andy Murray and Novak Djokovic will resume their battle for the No. 1 ranking.

Here are five things to look out for in the two-week tournament:

1. It's hot but ...

Unfolding during the Australian summer, temperatures often soar. Three years ago, the thermometer hit nearly 43 degrees Celsius (109 Fahrenheit).

One player, Canada's Frank Dancevic, said he glimpsed the cartoon character Snoopy while hallucinating in a first-round match against Benoit Paire.

Thanasi Kokkinakis changes his shirt during a 2014 match in Melbourne.

Dancevic passed out but somehow finished the contest.

"Until somebody dies, they're going to keep playing matches in this heat ... and personally I don't think it's fair," he fumed.

Despite the headlines the heat intermittently creates, Melbourne's weather can be notoriously fickle. Even in the summer, the saying goes that one can experience four seasons in a day -- temperatures can vary wildly from day to day.

Regardless, Federer has said more than once that the players should just get on with it.

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"If you've trained hard enough your entire life or the last few weeks and if you believe you can come through it, there's no reason you can't," Federer said at the 2014 Australian Open. "Just deal with it, because it's the same for both players.

"If you can't deal with it, throw in the towel.''

So what does this month hold?

According to a forecast from the tournament's meteorologist last month, there won't be consistent, scorching heat.

"We are expecting a very pleasant period weather-wise for Australian Open 2017," Bob Leighton said in a news release.

"Daily maximum temperatures for the second half of January are predicted to be around the low to mid 20s, and there could be three or four days in the 30s, with the possibility of one day in the high 30s."

The US Open -- where high temperatures regularly mingle with high humidity -- could be the most punishing grand slam from start to finish.

2. Downtown buzz

Located in southeast Australia, Melbourne has been voted the most liveable city by the Economist six years running, with "culture and environment" one category assessed by the magazine.

If players are keen to explore its diverse, often buzzing downtown core, they're not far away -- it's a short walk from Rod Laver Arena.

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A roughly 15-minute stroll from the tournament takes you to Federation Square, which often houses major events and is a general hangout area for tourists and Melburnians alike. Melbourne's main train station Flinders Street is nearby, too.

That isn't the case at the French Open and Wimbledon -- situated in southwest Paris and southwest London, respectively.

The US Open, meanwhile, takes place in the borough of Queens, far from bustling Manhattan. Reaching Flushing Meadows from Manhattan, where most players stay during the event, is 40 minutes by car -- without traffic.

Right beside Rod Laver Arena is the MCG -- Melbourne Cricket Ground -- the city's top-rated sight on Tripadvisor.

3. A night session -- every day

The US Open is famous for its night matches: New Yorkers can get loud, raunchy and raucous, holding nothing back.

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But the Australian Open has the US Open beat in the sheer number of night sessions. Unlike in New York, matches are scheduled at night every day of the fortnight, including both singles finals.

The latest finish in grand slam history came in Melbourne, not Flushing Meadows, when home favorite Lleyton Hewitt beat 2006 finalist Marcos Baghdatis in a five-set marathon at 4:34 a.m. nine years ago.

Hewitt and Baghdatis only began their match at about 10 minutes to midnight because earlier in the day Federer needed four and a half hours on the same court to dispatch Janko Tipsarevic. They also had to wait for the conclusion of Venus Williams' clash with Sania Mirza -- the first night match on center that day.

Two paid sessions per day on most days on Rod Laver Arena helped the tournament draw a record 720,363 spectators in 2016, about 30,000 more than the US Open.

4. It has a nickname

The Australian Open can lay claim to being known as the "Happy Slam." It was none other than Federer who coined the expression.

"You get here and are happy to play again," he told reporters in Australia in 2007.

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Players are refreshed after the off-season, not weighed down by eight months of wear and tear and traveling like when they arrive at the US Open.

The players have also long lauded the tournament's transport system and facilities.

Europe-based pros celebrating the Christmas holidays at home can escape chilly climes once the new year comes and soak up the atmosphere in Australia, where children are still on summer holidays.

5. Nowhere has more roofs

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Melbourne Park features stadiums with not one, not two, but three retractable roofs -- easily bettering the other majors.

Wimbledon and the US Open have cover on one court, while the French Open has none and was criticized -- again -- in 2016 when rain deeply affected the year's second grand slam.

Australian Open organizers added the third roof, on Margaret Court Arena, in time for the 2015 tournament.