A rare series of storms had cooled the summer air to an almost tolerable level, though it was steamy as ever inside Floyd Mayweather Jr's gym, just a few miles from the Las Vegas Strip.
With a couple of sparring partners in front of him late on Monday afternoon, Mayweather turned up the heat even more.
"Right there, right there," he yelled at the first hapless pugilist to feel his wrath. "You can't get away. I'll hit you when I want to."
It did not take Mayweather long to do just that. As the third of four rounds stretched to the 10-minute mark, he connected with a rapid volley of punches, finishing it off with a left hook that rocked his opponent for the day, sending him stumbling across the ring.
All in a day's work, but there was still work to be done. There always is when Mayweather is in training, and especially now, less than three weeks before his fight with undefeated Mexican star Saul "Canelo" Alvarez.
It is a big fight, but all Mayweather fights are big. He is the undisputed pay-per-view king. Though Mayweather's last fight in May against Robert Guerrero – for which he earned $32 million (Dh117.5m) – was not a huge box-office smash, the September 14 bout should make network executives at Showtime and CBS feel better about the money they laid out for boxing's biggest draw.
Better yet, he is fighting for the second time in four months, after not fighting more than once a year since 2007.
"I'm ready to perform and entertain, that's what it's all about," Mayweather said. "I'm a lot older now, so the last five fights I have, I want to go out with a bang."
The fight is the second in his six-fight deal with the Showtime network. He says the bouts will be the last of his career, though at age 36, he does not seem to have lost any of the reflexes or speed that have helped him win all 44 of his fights in a professional career that began following the 1996 Olympics.
What has changed is how Mayweather sells himself, even if he claims he has not changed. Ever since his release from a Las Vegas prison after serving 64 days on domestic-abuse charges last year, Mayweather has been the model of politeness and civility – in sharp contrast to the bad-boy persona that made him such a big attraction over the years.
That is one reason why Showtime's All Access TV show on Mayweather-Alvarez seemed to fall flat in the first episode.
There were the requisite shots, of course, of Mayweather and Alvarez in face-offs and together on a tour promoting the bout, but there was not the drama of Mayweather's earlier fights when he could be seen yelling at his father or counting stacks of $100 bills with his former buddy, the rapper 50 Cent.
That sold pay-per-views to people who spent their money hoping to either see Mayweather win or get knocked out. But Mayweather seems to either have outgrown the part or simply does not want to play it anymore.
"What do you mean by image? My image has always been as an entertainer, but at home I'm a great father," Mayweather said. "There's no bad guy, that's an image the critics picked. My image is to make sure my kids get the best education and provide a comfortable life for my family."
If the new Mayweather is a kinder and gentler sort outside the ring, he has changed some inside, too. His fights sometimes tended to become tedious affairs as he sought to win without getting hit, but in recent years, he has changed his style somewhat and has become more aggressive and flat-footed.
It showed on Monday as he walked two sparring partners across the ring, banging away with left hooks and right hands while keeping up a steady stream of chatter. The short time between fights should be beneficial to Mayweather at his age, and he is already inside the 152-pound (69kg) catch weight for the fight.
"I got back into it so quick that I'm still sharp," he said. "I feel good, real good."
Boxing fans should feel good, too, that Mayweather is taking on Alvarez, 23, who is unbeaten in 42 fights and holds a piece of the 154-pound title. Mayweather has been criticised in the past for hand-picking his opponents and refusing to fight Manny Pacquiao, but Alvarez is as dangerous as any fight he could take on at this stage of his career.
Not that Mayweather will acknowledge any such thing. Icing his sometimes brittle hands while sitting in a dressing room after his workout, he questioned the quality of Alvarez's opponents, and said it was just another fight to him.
Another fight and another $40m payout that will cement his reign this year as the highest-paid athlete in the world.
As for Pacquiao and the fight that will likely now never happen?
"I don't even know who that is," Mayweather said.