Ahead of today's qualifying session, the air temperature is 17.2 degrees C, while the track temperature is 25.7 degrees. Race control confirms a 100% chance of rain.
Anyone in any doubt about Max Verstappen and Red Bull this weekend will have been given a very clear wake-up call earlier. Though the Austrian outfit looked a little off the pace yesterday, it well and truly stamped its authority on this morning's session, especially in the world champion's case.
Out=pacing even his teammate by 0.4s, the Dutchman looked awesome, and clearly Ferrari and Mercedes has a tough call on its hands.
Though both Ferrari and Mercedes looked strong yesterday, this morning they were barely in the game, though there is a sizeable gap to the best of the rest.
With this session likely to be 'rain free' it remains to be seen whether the Weather Gods will lend assistance tomorrow.
Best of the rest earlier was Lando Norris, McLaren having looked strong yesterday, ahead of Valtteri Bottas, Mick Schumacher and the Alpines.
Off the pace earlier were both AlphaTauris, along with Ricciardo and Magnussen, all of whom will be seeking an improvement over the next hour.
In the moments before the start of the session, there is frantic work ongoing on Perez' car, while at Mercedes the mechanics are also quite busy.
Meanwhile, all bets are off, for with around 8 minutes before the green light, the rain begins to fall.
"Change in climatic conditions," race control calmly advises. Indeed, it's more November than July, wet and windy.
With heavier rain on the way, it is understandable that there is queue of cars at the end of the pitlane, Williams, Aston Martin and Haas leading the way, looking to take advantage of any upsets.
Latifi is first out, followed by Schumacher, Albon, Schumacher, Vettel, Magnussen and Leclerc, who is the first of the big guns.
Soon all bar the Alpines are on track, all sporting Inters.
Ricciardo is told the rain should stop in the next eight minutes.
Latifi posts a 52.55, Albon a 49.914 and Leclerc a 47.521.
Bottas brings out the yellows when he spins at Vale.
Sainz goes second, ahead of Ricciardo and Albon, but all are demoted when Hamilton goes second and Russell third.
However, a 45.743 sees Verstappen go top, as Albon improves to second (46.991).
A 43.028 sees Leclerc go quickest as the times continue to tumble.
A Vettel pits, with 11:10 remaining, the Alpine pair head out.
Hamilton goes second, Russell third and Norris fourth, but a 48.303 from Perez sees them all demoted.
Leclerc consolidates his top spot with a 42.129, as teammate Sainz posts a 43.463 to go third.
Russell goes third and Bottas seventh, the times constantly changing.
Ocon's first flying lap sees the Frenchman go 18th, while teammate Alonso posts a 44.685 to go 11th.
Russell goes quickest (41.743), but as the crowd cheers Verstappen responds with a 40.452 and Leclerc a 40.785.
Schumacher improves to 15th and Latifi 12th.
Gasly improves to 14th with a 43.772.
Leclerc improves with a 40.630 but remains second, 0.178s off Verstappen's pace.
Zhou goes fifth with a 41.854, as Ricciardo goes off at Village.
Norris claims he was impeded by Tsunoda.
With 3:00 remaining, Gasly, Latifi, Stroll, Ricciardo and Schumacher comprise the drop zone.
Bottas improves to seventh with a 41.871, as Hamilton posts a 40.460 to go second.
Norris goes seventh (41.515), while Ricciardo can only manage 13th (43.001).
Russell goes quickest in the opening sector, as Latifi goes tenth overall.
Magnussen goes tenth, as Russell abandons his lap and Verstappen looks set to improve.
Gasly goes eighth as Verstappen posts a 39.129 just moments after Leclerc had momentarily gone quickest with a 39.846.
Ricciardo improves to 14th, while Schumacher fails to improve, as does Vettel.
Zhou goes seventh as Latifi leapfrogs his Williams teammate to go fifteenth and score his best qualifying result of the year.
"My God, guys, why are we doing cool down laps?" asks Albon, "honestly guys, I had no grip."
Quickest is Verstappen, ahead of Leclerc, Russell, Sainz, Hamilton, Perez, Zhou, Bottas, Norris and Alonso.
We lose Albon, Magnussen, Vettel, Schumacher and Stroll, both Aston Martins out for the second successive race weekend.
Russell is warned that there will be light rain in Q2 and Q3.
Eager beaver Latifi is waiting at the end of the pitlane for the start of Q2. He is followed out by the Alfa pair, the Alpha pair, Ocon, Norris and Alonso.
Last out are the Mercedes pair, Hamilton immediately complaining of a "massive vibration" on his tyres.
Latifi sets the benchmark with a 45.161, but this is soon eclipsed by Bottas, Tsunoda and Zhou (44.029).
A 43.121 sees Alonso go top, only to be demoted by Perez (42.513) and then Verstappen (41.486).
A 42.682 sees Hamilton go third, ahead of Russell, Alonso, Leclerc and Tsunoda.
Norris goes quickest in S2, subsequently crossing the line at 41.821 to go second.
As the rain increases in intensity, Verstappen consolidates his top spot with a 40.655.
As conditions worsen, Latifi improves to 9th, while Sainz has dropped to 14th.
Alonso goes sixth with a 42.209 as countryman Sainz improves to fourth with a 41.602.
With 5:40 remaining, Gasly, Bottas, Tsunoda, Ricciardo and Ocon comprise the drop zone, the heavy rain meaning that there are few greens on the timing screen, far less purples.
"It's raining quite a bit more," observes Leclerc.
"It's getting too bad, I'm starting to aquaplane a lot," advises Norris.
Ocon posts a PB in S1, however an aquaplaning moment in S2 sees him abort the lap.
"Can't see," is all Bottas has to say.
Ocon goes for another lap, but he almost loses it as he enters the Wellington Straight.
Verstappen is quickest, ahead of Hamilton, Leclerc, Sainz, Russell, Norris, Alonso, Perez, Zhou and Latifi.
We lose Gasly, Bottas, Tsunoda, Ricciardo and Ocon.
Check out our Saturday gallery from Silverstone here.