Ahead of today's qualifying session the air temperature is 21 degrees C, while the track temperature is 24 degrees. It is cooler than yesterday, and with a 30% chance of rain.
Courtesy of the Weather Gods the drivers were unable to completed their qualifying sims earlier, while yesterday's sessions were compromised by the need to try Pirelli's prototype hards.
The first half of the F2 race that followed this morning's session was hit by rain, but now the circuit has dried and the sun is shining. However, there is talk of further rain over the next hour.
Despite this, qualifying is unlikely to be the sort of lottery one might expect in Monaco, though we could still be in for some surprises.
With the various upgrades finally getting to stretch their legs, Hamilton warns it will be a "struggle" to make it into Q3, while neither of the Ferrari drivers appears fully convinced the direction their team has taken.
Consequently one expects Red Bull to pick up where it left off, while Alonso remains the main challenger. The Alpines have looked good so far this weekend, as has Hulkenberg, while McLaren is likely to be in the mix.
At Williams the team have been working "tirelessly" repairing Sargeant's car, the American having crashed this morning and causing a red flag stoppage that further compromised track time.
Ahead of the green light, the partisan crowd is clearly up for it.
"It's raining trackside," confirms race control as Tsunoda leads the way, followed by Russell, de Vries, Ocon and Hamilton.
"It's spitting in the pitlane," reports Russell, "but very, very lightly."
Tsunoda goes off at T11, bringing out the yellows, the Japanese having been just a little over enthusiastic.
"The rain is on the way," says Russell as the Ferrari pair are last to emerge.
Russell gets things going with a 15.735, while Ocon responds with 14.820 and Gasly a 14.618.
Alonso has a major wobble in the final corner, riding through the gravel, and can only manage a 16.170.
The session is red flagged after Bottas goes off at T14, the Finn calling on his team to check his floor. There was another off for Albon, the Williams drivers reporting that he "bottomed the car quite badly" when he rejoined the track.
The clock has stopped with 14:13 remaining with only 8 names on the timesheet.
Hulkenberg has gone quickest before the stoppage but his time was subsequently deleted for exceeding the track limits at T5.
The session resumes, as Leclerc is warned of "just a few drops at Turn 1".
Bottas leads the way, followed by Zhou, Leclerc, Sainz and Perez.
Soon all bar the Mercedes pair are on track.
Zhou goes quickest with a 14.273, while Sainz can only manage 14.360 and Leclerc 16.618.
Verstappen posts a 13.660, while Piastri goes second (13.691) and Ocon third.
Alonso goes sixth while de Vries briefly brings out the yellows when he spins at T11.
Sainz is unhappy when he finds his way blocked by a slow Gasly who appears to be stuck behind a slow Leclerc.
A 14.045 sees Hamilton go third, while Bottas posts a 14.613 to go eighth.
Perez can only manage 13th, while his teammate consolidates his top spot with a 13.615.
Norris goes seventh with a 14.528. However he is demoted when de Vries posts a 14.372.
Leclerc can only improve to 16th, the Ferrari driver clearly struggling for grip. That said, Russell is eighteenth as he too struggles.
Russell subsequently improves to eighth, thereby dropping Perez into the danger zone.
Adding to his misery, Leclerc, who has been complaining about his rears, is called to the weighbridge.
With 3:30 remaining, just Stroll, Perez and the Williams pair are on track.
Stroll goes third with a 13.766, as teammate Alonso heads out.
All twenty drivers are on track, nearly all sporting fresh rubber.
Perez improves to fourth with a 13.874, which should be enough.
The stewards have noted an impeding incident involving Verstappen and Gasly.
Albon goes sixth, but is demoted when Gasly goes quickest with a 13.471.
Hulkenberg goes top with a 13.420 and Alonso fifth (13.474).
Ocon and Russell trade fastest sectors, the Frenchman going second with a 13.433.
Norris hoes quickest but is demoted by Hamilton, while Leclerc aborts his lap and fails to make the cut.
Zhou goes tenth.
"We are out, yes," asks Leclerc. When told that he is, he replies: "unbelievable!"
Phew! Quickest was Hamilton, ahead of Norris, Russell, Sainz, Hulkenberg, Ocon, Gasly, de Vries, Verstappen and Zhou.
We lose Bottas, Magnussen, Albon, Leclerc and Sargeant.
Alonso reports that Gasly did a "big impeding" of Verstappen in Turn 4 and "deserve 3 places".
Verstappen is first out for Q2, followed by Perez, Sainz and Tsunoda.
The Dutchman posts a 12.760, albeit on fresh rubber, while his teammate, on old rubber, crosses the line at 13.614. Sainz goes third with a 13.790.
As more drivers head out, Hamilton goes quickest in S1. However, he subsequently aborts the lap.
Russell goes third, but is demoted when Alonso bangs in a 13.278 and Ocon a 13.372.
Stroll goes fourth and Gasly sixth as Hamilton goes quickest in S1 once again. At the line the seven-time world champion posts a 12.999 to go second, 0.239s down on Verstappen.
"The front is opening up massively," reports Zhou.
"Bloody Nora, I'm really struggling, the car is bouncing and all over the place, no confidence," says Russell.
Now it's Hamilton's turn to visit the weighbridge.
"I don't have the answer for now," says Leclerc, "the left hand corners were undriveable and the right hand corners was similar to this morning.
"It was very far off from what I expected," he admits. "I just had no grip from the rears, we will check, but I'll be very surprised if everything is fine with the car. It was just very, very weird behaviour."
The final assault gets underway.
Oh dear, a mistake sees Perez off and in the gravel at Turn5. He is able to continue.
Hulkenberg improves to fourth with a 13.283, while Sainz goes second with a 12.790.
Gasly goes fifth, but is demoted by Stroll who crosses the line at 13.082.
Norris goes second having been quickest in S3, while McLaren teammate Piastri posts 13.059 to go sixth.
Tsunoda can only manage eleventh, while Russell fails to make the cut as does Perez who can only improve to 11th.
"Unbelievable," sighs the Mexican.
"Nowhere," says Russell as he subsequently clashes with his teammate.
"That was dangerous," says Hamilton. "You didn't tell me there was a car behind," says Russell. The incident will be investigated after the session.
Quickest is Verstappen, ahead of Norris, Sainz, Hamilton, Ocon, Piastri, Stroll, Alonso and Gasly.
We lose Perez, Russell, Zhou, de Vries and Tsunoda.
Check out our Saturday gallery from Barcelona here.