Ahead of today's sole practice session the air temperature is 24 degrees C, while the track temperature is 35 degrees. Once again it is bright and sunny.
Despite the countless laps Mercedes has run here over the years, the team admits to having taking a "wrong turn" for Thursday's second session, in terms of set-up.
Consequently, all eyes will be on the German team today to see whether FP2 was indeed a blip or whether F1 W08 EQ has more profound issues here, after all, there were fears the car's long wheelbase might compromise the team.
With Pirelli admitting that the ultrasoft tyres can last the entire race, Hamilton and Bottas need to be a lot closer to the front than 8th and 10th.
Impressive in both sessions was the Toro Rosso duo, 4th and 5th in FP2 and also very strong in the opening session, sticking to supersofts when everyone else was on the ultras.
The lights go green and Wehrlein leads the way, followed by Raikkonen, Ericsson, Magnussen, Sainz and Vettel.
As more drivers head out, most are on softs, though Wehrlein, Ericsson and Palmer have opted for the ultras. Strangely, no supersofts.
Wehrlein posts the first time of the day (19.583), but this is soon beaten by Ericsson and then Palmer (17.701). The Briton subsequently improves to 16.075.
Seven minutes into the session the Bottas finally appears, the Finn, on ultras, immediately posting 15.249 to take the top spot. Perez, Kvyat, Ocon and Hamilton yet to appear.
Honda reveals that the turbocharger and MGU-H has been changed since Thursday and as a result Button takes a 15-place hit. Welcome back Jenson.
As Hamilton heads out, Bottas improves to 14.122, ahead of Hulkenberg and Palmer.
Raikkonen is on track, on the ultras, and immediately goes quickest in S1. However, moments later Bottas goes quicker in the same sector.
As Hamilton posts 26.461, Raikkonen crosses the line at 13.568, while Bottas stops the clock at 13.621.
As Hamilton improves to 14.736 (5th), Raikkonen goes quickest in S1 but a mistake at Rascasse means he fails to improve.
As Ocon goes third and Perez fourth, Vettel heads out on a set of ultras.
A 14.065 sees Hamilton go third, albeit 0.497s off Raikkonen's pace.
As Vettel posts 14.090 to go fourth, Grosjean locks-up at Mirabeau and has to head down the escape road.
16 minutes in and all but Magnussen, Vandoorne, Ricciardo, Massa and Verstappen have posted times.
AS Vettel goes second (13.414), Raikkonen consolidates his tops spot with a 13.379, leaving Bottas 0.242s in his wake.
On his first flying lap, Kvyat posts a mighty impressive 13.791 to go fourth, only to be demoted when Hamilton posts 13.230.
However, the Briton isn't on top for long, moments later Raikkonen retakes the top spot with a 13.013 only for Vettel to bang in a 12.890.
Verstappen joins in the fun and games, taking fourth with a 13.262, the top six covered by 0.901s. Elsewhere a massive lock-up at Ste Devote for Ricciardo.
Ocon is unhappy at being blocked by Magnussen, who has slowed to a halt in front of the Frenchman to find some clear track - and rightly so - "that's Monaco mate," is the response from his engineer.
A 13.848 sees Vandoorne go eighth, while teammate Button is currently tenth.
Finally getting a lap together, Ricciardo posts 13.830 to go eighth.
Another strong lap from Kvyat sees the Russian go fifth as teammate Sainz seeks to improve on ninth.
Despite his best efforts, Hulkenberg is unable to improve on 16th (14.977), the German one of many struggling with his tyres.
At 'half-time', it's: Vettel, Raikkonen, Hamilton, Verstappen, Ricciardo, Kvyat, Bottas, Vandoorne, Sainz and Button.
Check out our Saturday gallery from Monaco, here.
Verstappen goes quickest in S1, subsequently crossing the line at 12.940 to split the Ferraris. Despite PBs in the final two sectors however, Ricciardo remains fifth.
The Ferrari duo head back out, both sporting brand new sets of ultras. We're wondering in someone will try the supers for a qualifying sim at one point.
Also on a new set of ultras is Bottas who posts a PB in S1. Elsewhere, Hamilton is told that he has to wait until his second lap before he can really push.
A PB in S1 for Raikkonen while Vettel posts a purple. The German maintains his pace in S2, finally crossing the line at 12.558 while the Finn retakes second with a 12.875.
Much like Friday, Bottas is unable to improve and has slipped to seventh, while Hamilton also appears to have got the very best out of his car (and tyres).
With the Red Bulls and Toro Rossos likely to improve, this is looking bad for Mercedes.
No such problems for Vettel who again goes quickest in S1. Again he maintains the pace in S2, subsequently crossing the line at 12.395.
Bottas digs deep to produce a 12.987 which puts him fourth, but demotes his teammate in the process.
PBs in the first two sectors result in a minor improvement for Raikkonen (12.740), the Finn now 0.345s off his teammate's pace.
Magnussen improves to ninth with a 13.755 as Bottas continues to try and close the gap to the Ferraris, the Finn currently third, 0.435s off the pace.
Ocon is in the barriers at the Swimming Pool exit, meaning the VSC is deployed.
With 8 minutes remaining, this will compromise the qualifying sims that the drivers were about to begin.
Replay shows the Force India repeating Verstappen's mistake of twelve months ago, clipping the inside barrier and thereby breaking the steering arm.
"I crashed the car guy," he says sheepishly.
Despite the efforts of 13 (thirteen, count 'em) marshals, they make a right pig's ear of removing the car. And as the car swings back and forth, hitting the ground and the barriers in the process, Force India will not be happy.
The session resumes with 3:45 remaining... however, with the 19 remaining cars heading out traffic is going to be a major issue.
"Ocon provides a graphic illustration of the fact that the cars are 20cm wider this year," points out Pirelli.
Despite a PB in S2 Verstappen is unable to improve, while Bottas clearly doesn't see any point in staying out and pits, as does Hamilton. They subsequently head out again, possibly fully fuelled, in order to perform practice starts at the end of the session.
Moments after Kvyat goes too deep at Ste Devote, Ricciardo also takes to the escape road, subsequently reporting that his brake by wire failed. "The pedal just went to the floor," he sighs.
Needless to say, Monaco is the one circuit where you need full confidence in your brakes.
Vettel lead Raikkonen for a Ferrari 1-2, ahead of Bottas, Verstappen, Hamilton, Ricciardo, Sainz, Kvyat, Magnussen and Vandoorne.
Perez is eleventh, ahead of Button, Ocon, Massa, Hulkenberg, Grosjean, Stroll, Palmer, Wehrlein and Ericsson.
Check out our Saturday gallery from Monaco, here.