MELBOURNE, Australia—For the first time in 20 years, the Australian Open has changed its surface, from Rebound Ace, a slow, green hard court that produced high bounces, to Plexicushion, a blue hard court manufactured by the same company that developed the courts for the U.S. Open. Will it make a difference in the results down under?

Likely, the answer is no. But another new Australian Open feature — a modified heat rule — might matter a lot, depending on the weather in Melbourne the next two weeks. Right now, the forecast is mild, but it’s reasonable to expect at least one hot spell. When that heat arrives, how the new heat procedures are handled, and how players react to them, seems a far more interesting plot to watch.

First, some details about the surface and why you shouldn’t fret about it playing a role in the outcome of this tournament. Plexicushion purports to be different from the U.S. Open’s DecoTurf II courts, and the early returns suggest that it is indeed a bit slower and produces higher bounces (but lower than Rebound Ace).. So far, the players seem to agree that it is more predictable than the now deceased Rebound Ace, which, many players said, could play fast or slow, and produce different bounces, depending on the temperature at the time of play. Players also complained that Rebound Ace stuck to their sneakers and increased the chance of injury, something that has never been proven beyond anecdotal evidence. In making the surface change, tournament director Craig Tiley said he had two aims: to give competitors a more consistent surface and to give Australia’s juniors a consistent surface that is more similar to other hard courts around the world.

It’s early yet, but Tiley seems to have succeeded, or at least succeeded in choosing a surface that won’t offend anyone. Witness defending champion Roger Federer’s comments in his pre-tournament press conference yesterday.

“I think it’s very similar, just a bit slower maybe,” Federer said of the Plexicushion. He added that he didn’t care which hard court the tournament chose, as long as it stuck with its choice for a while. “They’ve changed the surface too many times in the last years here. So they better keep this one for the next 50 years.”

And why not? After all, we are talking about variations of a hard court, not something radically different like grass. Sure, the two hard materials are different (Plexicushion has less rubber than Rebound Ace), but it’s unreasonable — and illogical — to think that these new courts will change the nature of this tournament. No one in the men’s or women’s draws is more or less favored now than before. One can assume that finetuned athletes are more likely to notice slight differences between different hard courts than us regular folks, but they are also better equipped to adjust to those differences. The new surface is nice, but not much of a story unless something goes drastically wrong (it melts, bubbles, produces wildly unpredictable bounces, etc.). Don’t count on any of that happening.

The new heat rule is a different matter. In past years, different classes of players were governed by different — and unfair — rules. When the heat rule was invoked, players in the middle of matches were forced to finish in extreme conditions, even those players inside the two main stadiums (the tournament would not close the roofs in the middle of a match). But the stars, who always play inside the main stadiums, did have an advantage, because if they began a match when the heat rule was in effect, they would play indoors. As a result, there were times when a star played a match indoors in the shade while his or her next opponent, unlucky to have started before the heat rule went into effect, had to struggle in the heat.

Such a situation won’t arise this year. Once the heat rule goes into effect, all matches will continue until the set is finished. Those matches inside the main arenas will continue with the roof closed, and those outdoors will stop until the heat subsides. No one will be forced to finish a match in extreme heat. Though lesser players may have to deal with delays, it’s better to have a slight delay than to play in heat that saps your strength for your next match.

There’s been another important change, too. The previous heat rule automatically went into effect only if a specified combination of temperature and humidity was reached. This year, the tournament referee, Wayne McKewen, has the heat rule under his sole discretion. To help McKewen make the call, the tournament has built a weather station on the grounds and hired a meteorologist.

One could argue that the old rule did not adequately account for on-court temperature, which is much higher than the air temperature (hard courts absorb a lot of heat, and even though Plexicushion is said to retain less heat, the amount it does retain is incredibly high — you’d much rather walk barefoot on coals than a tennis court on a sunny, 100-degree day in Melbourne). The old rule didn’t always consider that weather in Melbourne changes quickly, either. In this climate, conditions harsh enough to invoke the rule can subside by the time the roof closes.

Of course, one could also argue that the new rule introduces a dangerous human element into the process — dangerous in the sense that when a person is accountable for deciding when play stops and begins, players, journalists, and spectators are bound, at some point, to become angry with that person, no matter how good his intentions (McKewen, you have been warned).

I’m much happier that a person will make the call this year. With the information available to him, McKewen shouldn’t have much trouble figuring out when it’s too hot to play. And if someone disagrees with him, well, that’s part of the fun, and certainly a lot more interesting than minute differences between two very similar hard surfaces that probably won’t affect the tournament at all.

Mr. Perrotta is a senior editor at Tennis Magazine. He can be reached at tperrotta@tennismagazine.com.