Ahead of Q1, the air temperature is 23 degrees C, while the track temperature is 31 degrees.
Though Lewis Hamilton topped the timesheets in both of yesterday's sessions, this morning it was teammate Valtteri Bottas who led the way. However, while yesterday's sessions were held in bright sunshine, Bottas posted this morning's benchmark shortly before the heavens opened up.
Since this morning's session, which saw only 15 drivers post times and only a handful of those in any way meaningful, the sky has brightened but there are still fears of further rain both late in the session and during the race tomorrow.
On the evidence thus far, Mercedes is the team to beat, Hamilton and Bottas clearly benefitting from the much anticipated upgrade delayed from Canada.
As ever, Ferrari is playing its cards close to its chest, but it will need to have something special in reserve if yesterday's pace from Mercedes was anything to go by.
Red Bull is clearly there or thereabout, and though down on power compared to Mercedes and Ferrari, we know from experience that the RB14 is the best chassis out there.
Best of the rest, certainly based on yesterday's running, is Haas, with force India, Toro Rosso and McLaren there or thereabouts.
That said, at what was already the great unknown for the drivers, the addition of the weather gods intervening can only be good for us. After all, looking at this morning's times - Bottas ahead of Sainz, Leclerc, Alonso, Vettel, Vandoorne, Gasly, Ericsson, Perez, Ricciardo, Ocon, Hamilton, Raikkonen, Stroll and Sirotkin - who wouldn't want to see the grid shape up in a similar way.
In the moments before Q1, though it remains bright, race control announces that there is a 60% chance of rain. Indeed, as was the case early in FP3, while the sky on one side of the circuit seems fine, dark clouds are appearing on the other side.
The lights go green and Stroll leads Vandoorne, Alonso, Gasly, Ericsson and a whole heap of others out on to the track. More and drivers head out, all on the ultrasofts.
"Williams will be much slower than us so open a good gap," Gasly is told. Make of that what you will.
Stroll gets things underway with a 34.725, while Sirotkin posts 34.752. Gasly eclipses the pair with a 33.766.
No sooner has Magnussen posts 32.956 than Haas teammate Grosjean stops the clock at 32.466.
Last out are Ocon and Raikkonen.
Leclerc goes third (33.057), ahead of Sainz and Hulkenberg, as the big guns begin their first flying laps.
Verstappen posts 31.823 to take the top spot, but Grosjean looks set to improve.
As Bottas posts a 31.776, Hamilton complains that "something is wrong with the padding on my lefT2. Nonetheless, he posts 21.589.
A 31.567 sees Raikkonen go top, while Vettel can only manage 32.089 and Ricciardo 32.402.
Following a cool lap the pace is raised once again and Hamilton, Bottas and Verstappen trade fastest sectors.
Quickest in S3, Verstappen posts 31.531 while Bottas responds with a 31.776.
As Hamilton posts 31.271 to go top, Vettel and Ricciardo look set to improve.
With 5:50 remaining, Perez, Alonso, Ericsson and the Williams duo comprise the drop zone, with Vandoorne, Ocon and Gasly hovering.
Ricciardo leapfrogs Vettel with a 31.910 to take fifth.
Grosjean and Magnussen are currently best of the rest, maintaining the form shown yesterday.
As Leclerc improves to tenth, both Force Indias remain in the drop zone.
Ericsson posts 33.124 to go 14th, Sauber currently looking good to get both cars into Q2.
For a brief moment Stroll is airborne as he runs wide and over the 'baguettes'.
Despite his best efforts Hulkenberg cannot improve on twelfth (32.949).
Ocon and Perez both posting PBs in the first two sectors, the Frenchman posting 32.786 to go 12th, while his teammate posts 32.692 to leapfrog him.
All of which drops Alonso into the danger zone along with McLaren teammate Vandoorne.
At the very end, both Magnussen and Hartley report drops of rain.
Quickest is Hamilton, ahead of Verstappen, Raikkonen, Bottas, Vettel, Ricciardo, Grosjean, Magnussen, Sainz and Gasly.
We lose Alonso, Hartley, Vandoorne, Sirotkin and Stroll. A sad days for two great British teams, both McLaren and Williams failing to get a single car through the first phase.
To compound Sirotkin's misery, he is being investigated for impeding Hulkenberg.
Verstappen heads the queue at the end of the pitlane, the remaining 15 drivers aware that the rain clouds are heading in. While most are on the ultras, both Red Bulls are on the supersofts. The McLaren duo also on the red-banded rubber.
No further action to be taken over that Sirotkin/Hulkenberg incident.
As they begin their flying lap, Hamilton is still complaining about a loose cockpit padding.
Verstappen posts 32.307 while Ricciardo posts 32.336 as the rain begins to fall.
Raikkonen posts 32.000 but is eclipsed by countryman Bottas who crosses the line at 31.227.
Hamilton goes top with a 30.645 on the supersofts, 1.355 quicker than the ultra-shod Ferrari.
After that first run, Hulkenberg, Leclerc, Perez, Ericsson and Ocon comprise the drop zone.
Raikkonen goes quickest in S1as the Mercedes pair head back to the pits. Vettel is also on a hot lap.
Ricciardo posts 31.538 and Verstappen 31.538, as Raikkonen goes second (31.104) only to be demoted when his Ferrari teammate posts 30.953, still 0.308s off Hamilton's pace.
Ahead of the final runs, Ocon, Leclerc, Ericsson, Hulkenberg and Perez still comprise the drop zone. Sainz and Gasly are hovering.
"Very stable, not making the track worse," replies Ricciardo when asked about conditions. It's still raining but it very light.
Perez improves to tenth with a 32.484, but is it enough?
Strangely, Vettel and Raikkonen head out again, still on the ultras. As des Ricciardo and Mercedes, all on ultras.
Grosjean goes quickest in S1, while Vettel goes purple in S2.
Hamilton also set to improve, the world champion quickest in S1.
Vettel remains second despite improving his time while Grosjean goes fifth (31.472).
Ocon improves to tenth which is bad news for his Force India teammate.
Bottas remains fifth while Leclerc takes tenth, thereby demoting Ocon.
Verstappen improves his time, but is still on the supers.
Hamilton aborts his lap, as does Ricciardo, both keen to start the race on the supersofts not the ultras.
Quickest is Hamilton, ahead of Vettel, Raikkonen, Verstappen, Bottas, Grosjean, Magnussen, Ricciardo, Sainz and Leclerc.
We lose Ocon, Hulkenberg, Perez, Gasly and Ericsson.
Both Force Indias out, while Hulkenberg is advised that he missed out by 0.6s, the German insisting that it was a "very good lap".
Check out our Saturday gallery from Paul Ricard, here.