Ahead of today's sole practice session the air temperature is 11 degrees C, while the track temperature is 16 degrees. Late next month we will be told that this July was the hottest ever on record.
While it has stopped raining for now, such were the conditions earlier that the F3 Sprint was postponed. Indeed, Race Control advises that there is an 80% chance of further rain over the next hour.
A number of drivers have taken on new power units, however it will probably be easier to tell you who hasn't, and that's Max Verstappen, Lewis Hamilton, Esteban Ocon, Alex Albon and the Ferrari pair.
Lando Norris was quickest in both of yesterday's sessions, however with rain anticipated tomorrow also, we could well be facing a lottery.
With the track still damp from the previous downpour the session is declared wet.
The lights go green and after a couple of minutes the Haas pair head out, followed by Sargeant, Tsunoda and Albon. All are on Inters.
Of the first wave, Alonso goes quickest (48.627), ahead of Tsunoda, Piastri, Ocon and Magnussen, however Leclerc stops the clock at 48.364.
"The track is wetter than expected," Ricciardo is told, "but will improve."
At which point Gasly spins off into the gravel heading into Vale, necessitating the session to be red-flagged. Moments earlier Verstappen had a 180 spin at Brooklands, while Tsunoda had gone top with a 47.080.
Ricciardo has been noted for a pitlane infringement, thought to involve the fact that he was weaving from side to side as he headed down the pitlane.
The session resumes, and Sargeant leads the way.
A 44.747 sees Piastri go quickest, but he is subsequently demoted by Hamilton and then Norris (43.697).
"The track is definitely drying a bit now," reports Russell as Tsunoda posts a 43.284.
As Bottas spins, Leclerc raises the bar with a 40.852.
Russell goes second (41.087), ahead of Piastri, Perez and Hamilton as Verstappen crosses the line at 40.319.
Having gone quickest in S1, Leclerc does well to keep the car on track at the rear end snap out in Club.
Hamilton goes top with a 39.546, the seven-time champ quickest in all three sectors.
As purple sector times illuminate the timing screen, Russell goes second with a 39.753.
Leclerc posts a 38.690 but Hamilton responds with a 38.511.
Quickest in the final sector, Norris goes fourth with a 39.118.
Leclerc crosses the line at 38.454, but Hamilton responds with a 38.065.
"At Turn 12 you can use more kerb," Sainz is told. "Don't use the radio, I was in the middle of Turn 7 (Luffield)," the Spaniard replies.
"The rain might get worse in fifteen minutes," Norris is told, with 28 minutes of the session still remaining.
Russell improves to 37.529.
With 25:00 remaining, it's: Russell, Hamilton, Norris, Leclerc, Piastri, Sainz, Verstappen, Perez, Hulkenberg and Alonso.
"It's starting to rain now," reports Verstappen as he has a big, big slide. "Yes, were aware of that," he is told, "box, box."
"It's level 1," Ricciardo is told of the rain, "it will be level 2 in five minutes."
"With this level of rain just expect the standing water to be increasing a little bit more," Hamilton is warned.
"The tyres aren't great and I'm not learning much," admits Bottas as he peels off into the pits.
Phew! Russell has a big snap in the final corner, but keeps it all under control.
With little running and certainly no improvements, the session ends.
Russell is quickest, ahead of Hamilton, Norris, Sainz, Verstappen, Leclerc, Piastri, Alonso, Perez and Hulkenberg.
Albon is eleventh, ahead of Stroll, Sargeant, Tsunoda, Bottas, Ocon, Magnussen, Ricciardo, Zhou and Gasly.
Check out our Saturday gallery from Silverstone here.
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