Things change quickly in the desert this time of year, from blistering sun to blackest night, from annoying swelter to rattling chill.
From growing national title hopes to virtually none.
So it went for the USC football team, which stalked across the sagebrush to win a game, but will trudge home having probably lost a season.
In the game in front of them Saturday night, they overcame dropped passes and dumb turnovers with a suffocating defense to defeat Arizona, 17-10.
In a game almost 2,000 miles away, they had no such luck with Penn State.
In Columbus, Ohio, the unbeaten Nittany Lions remained that way in defeating Ohio State, 13-6.
That means Penn State, with three easy finishing games, probably will occupy one spot in the national title game.
Which means the other spot will surely go to either the SEC or Big 12 champion, both leagues containing enough unbeaten or strong one-loss teams to squeeze USC out.
Yeah, USC really, really, really needed Penn State to lose.
Yeah, the earlier loss to Oregon State will haunt the Trojans from Miami to Pasadena.
Not only will they probably miss the national title game, they could also miss the Rose Bowl, as Oregon State controls its destiny there.
Left for the one-loss Trojans -- if they indeed finish with that one loss -- would be spilled Sugar, peeled Orange or a flaky Fiesta.
Big-money games, certainly. Fun-and-sun games, all.
But USC is about national titles, especially a USC team that Pete Carroll proclaimed as perhaps his best.
As Saturday again showed, this one clearly isn’t.
Against a shaky Arizona team with losses to New Mexico and Stanford, USC took the lead, blew the lead, needed a third-quarter drive to regain the lead, then could barely hold the lead.
Four times, the USC offense had the ball in the fourth quarter with a chance to finish the Wildcats. Four times, the Trojans did nothing, one missed field goal and three punts.
“We made it really hard on ourselves,” said quarterback Mark Sanchez. “We really hurt ourselves, and we have to learn from it.”
Only several great defensive stands saved USC, including a fourth-and-one stop near midfield midway through the fourth quarter,
“A play like that determines who you are,” said Rey Maualuga, the leader of a group that held Arizona to a season-low 188 yards.
The identity of that defense is clear. Having given up one touchdown in the last 14 quarters -- and that on a 15-yard drive -- it deserves a shot at the title game.
The offense? Not so much.
USC survived, but what was so flashy so long ago against Ohio State has become mistake-prone and ordinary.
Even with all that speed, the offense stalls. Even with all that talent, the offense bores.
This wasn’t the first time this season. There appears to be no indication that this will be the last.
Sanchez had a couple of high or wide throws. The receivers had a couple of drops. The only consistent force was running back Stafon Johnson, and it happened only after the Trojans kept him in the game for seven runs during one drive.
It was in the second quarter. Johnson ended the 80-yard drive with a two-yard touchdown run to give the Trojans a 10-3 lead.
And, oh yeah, Johnson’s 54-yard punt return had earlier led to the Trojans’ field goal.
Johnson’s not flashy, but he runs hard, and he runs consistently, and it would be nice to see what he could do if he was given 20 carries a game.
“It was my best game,” Johnson said, “but it could have happened to any of our running backs.”
He’s just being nice. USC needs to pick one running back -- Johnson -- and stick with him. Because of the rotating backs, the focus of the offense is completely in the hands of Sanchez’s swagger.
Usually, that swagger is good. Sometimes, that swagger is bad. Before the game, that swagger was hilarious.
During warmups, thousands of red-shirted Arizona students filled the lower section of Arizona Stadium.
Sanchez strolled over anyway, right in front of them, to throw passes to Patrick Turner and Damian Williams, and the fans cursed him.
Sanchez threw and grinned, did everything but turn and wave.
But then there was the troublesome Sanchez swagger, in the third quarter, when he was running around the backfield with the ball swinging from one hand.
Smack. Slap, Fumble, Arizona ball on the USC 15-yard line. Four plays later, Arizona touchdown and a 10-all tie.
Now back to the good swagger, Sanchez immediately coming back to lead the Trojans to the game-winning drive that ended on a 30-yard touchdown pass to wide-open Stanley Havili.
Once again, the key was Johnson, as he threw a body-flipping block on a blitzing safety Nate Ness to protect Sanchez on the throw.
“I was thinking about the cussing I would get if I didn’t throw that block,” Johnson said with a grin.
It was a championship play, and USC still has several weeks to make championship plays.
But after Saturday, it appears too late for the Trojans to turn any of them into a championship.