Ahead of today's sole practice session the air temperature is 18.3 degrees C, while the track temperature is 27.8 degrees.
Ferrari led the way on Thursday, but it is doubtful if that will continue to be the case today, far less tomorrow.
Nonetheless, the Prancing Horse could still leave Monaco with a decent haul of points, having only failed once this season to get both drivers in the points.
Consequently, it looks like, as ever, it's going to be Red Bull and Mercedes, or rather Max and Lewis. That said, the Dutchman was somewhat downbeat on Thursday, unhappy that his car lacks speed.
Here more than anywhere else, both title protagonists will need the full support of their teammates, consequently the onus will be on Bottas and Perez to raise their games.
Talking of raising games, Tsunoda really needs to rediscover his mojo. Already on a slippery slope ever since his excellent debut in Bahrain, the Japanese youngster did himself no favours when he crashed in the final moments of FP2.
Also looking to take a significant step forward today is Ricciardo, who admits to being "frustrated" and "confused" by his lack of pace.
As for Mazepin, he'll be happy just to get through this most demanding of weekends unscathed.
Overnight rain has washed away much of the rubber deposited on Thursday and Friday, which will surely add to the driver's problems over the next hour.
Indeed, there is a 40% chance of further rain over the next 60 minutes.
The lights go green, but it is several minutes before a driver ventures out... and when he does, that driver is Raikkonen, a one-time winner here (2005).
He is followed by his Alfa Romeo teammate. Both are on softs.
As Raikkonen begins his first flying lap, Ricciardo, Tsunoda, Mazepin and Schumacher head out, the Haas pair on hards.
Raikkonen exploratory 24.937 is immediately bettered by his teammate (16.087). The Finn subsequently posts a far more sensible 14.293.
Ricciardo goes second with a 14.792, 0.499s down on Raikkonen.
Leclerc is the first of the big guns to head out, the Monegasque on softs. He is followed by his Maranello teammate.
Giovinazzi posts a 13.946, but Raikkonen responds with a 13.432.
Leclerc posts 23.371 and Sainz 20.220 as the drivers continue to settle down.
Sainz goes top with a 13.300, but, quickest in the opening two sectors, Leclerc responds with a 12.633.
As was the case on Thursday, Ricciardo is talked through certain corners by his engineer.
The Australian goes fifth (14.151), ahead of Norris, Alonso, Tsunoda and Stroll.
13 minutes in and all bar Ocon and the Mercedes pair are on track.
Latifi and Leclerc are among the first to have their time deleted for exceeding the track limits at Turn 10.
No sooner has Sainz posted a 12.533 than Leclerc stops the clock at 12.223.
Norris goes third (13.155) only to be demoted when Giovinazzi crosses the line at 12.563.
Verstappen goes 6th on softs (13.360), while teammate Perez, on mediums, posts a 14.994 t go 13th.
Ocon and the Mercedes pair finally head out as Leclerc raises the bar with an 11.658.
A 12.495 sees Verstappen improve to third, while Perez subsequently posts a 12.367 to demote his teammate.
Hamilton posts a 13.278 and Bottas 12.370 as the Black Arrows get to work.
Verstappen goes second with an 11.759.
A string of expletives from Gasly who feels he was impeded by Perez. In all honesty, he was.
As Verstappen goes quickest in S1, Hamilton improves to fifth with a 12.239.
Vettel and Ricciardo are the latest to have their times deleted. Leclerc and Bottas subsequently join 'the club'.
Verstappen goes quickest (11.485) and Perez fourth (12.135). The Bulls currently sandwiching the Ferraris. Perez, remember, is on the mediums while the rest are on softs. The next highest placed medium runner is Gasly in 9th and Latifi in 15th.
Sainz goes quickest in S1, maintaining a strong pace in S2. At the line he posts 11.452 on 13-lap old rubber.
Hamilton improves to fourth (12.020), but is 0.568s off Sainz' pace. Bottas posts a 12.084 to go fifth.
Leclerc goes quickest in S1, but overdoes it at the chicane and subsequently brushes the barriers at the swimming poll. Unsurprisingly he fails to improve.
It's: Sainz, Verstappen, Leclerc, Hamilton, Bottas, Perez, Norris, Giovinazzi, Gasly and Stroll.
At 32:00, as we ll take a deep breath, the Mercedes issue appears to be the inability to generate enough heat into its tyres.
As Norris and Sainz almost come to grief at Rascasse, Bottas locks-up at the chicane.
With 23:00 remaining, Sainz heads out on a fresh set of softs, as Raikkonen improves to 8th with a 12.460.
As Sainz is about to start his flying lap he finds a number of other drivers heading out just ahead.
Soon there are 14, 15, 16 drivers on track.
Leclerc makes use of the run off at Ste Devote, while Bottas follows suit moments later.
Norris goes fourth (11.988) as Latifi clouts the barriers at the swimming pool exit.
The session is red-flagged, which is a disaster for all, but mostly Mercedes.
As marshals swarm over Latifi's stricken Williams, the car has sustained significant damage to its right-front suspension.
Replay shows the Canadian rode the kerb at the exit of the swimming pool and clouted the barrier on the inside before heading across the track and clouting the barriers on the other side of the track.
"****, I crashed, I did," says the Canadian.
The all-clear is given with 12 minutes remaining.
Verstappen and Hamilton are among the first out, the Dutchman leading the way.
Quickest in S2, Verstappen can only manage a PB in S3 and consequently
fails to improve having had a poor opening sector.
Bottas posts a PB in S1, as do Hamilton and Perez.
Bottas aborts his lap due to traffic, while Perez goes fourth (11.822). Hamilton aborts his lap in the second sector.
"We've lost the GPS," Verstappen is told, "so keep your eyes on your mirrors."
Perez complains that he was blocked by the Ferraris.
Verstappen goes quickest in S2, crossing the line at 11.254.
Bottas posts a PB in S1, the Finn maintaining the pace in the second sector. At the line it's 11.765 to go fourth.
Perez improves his time but remains fifth.
Verstappen goes quickest in S2, but aborts in the final sector.
The session is red-flagged as Schumacher crashes after exiting Casino on the run down to the hairpin.
"I don't know what to say," admits the German, "I'm sorry about that."
The Haas is badly damaged, but it is unlikely that the car will be repaired in time for qualifying.
Replay shows he simply carried too much speed as he exited Casino Square.
The session will not be restarted.
Verstappen is quickest, ahead of Sainz, Leclerc, Bottas, Perez, Norris, Hamilton, Raikkonen, Gasly and Vettel.
Giovinazzi is eleventh, ahead of Stroll, Ricciardo, Schumacher, Alonso, Mazepin, Russell, Latifi, Tsunoda and Ocon.
Check out our Saturday gallery from Monaco, here.