Ahead of today's sole practice session the air temperature is 22 degrees C, while the track temperature is 29 degrees. It is overcast and very windy

With no need to run Pirelli's prototype hards today, the teams are free to get down to the business of trying out those all-important upgrades ahead of qualifying.

While Charles Leclerc is pretty non-committal in terms of Ferraris, Lewis Hamilton believes he will struggle to make it into Q3.

Feeling a lot happier on the other hand are Alpine, Haas and Alfa Romeo, while McLaren is giving nothing away.

Though he out-paced his rivals by 0.7s in FP!, in the afternoon they appeared to close the gap... though we stress the word appeared, for the Dutchman and his team seem mighty confident.

As was the case yesterday, there is much support for local hero Alonso.

The lights go green and with an eye on the increasingly darkening sky there is a mad scramble to get out on track, Sargeant leading the way from Albon, Magnussen, Hulkenberg and de Vries. All three compounds are in use.

In the distance there is lightning. "Rain is expected in nine minutes," Ocon is told.

"Light rain to start with, then increasing in intensity," Russell is warned.

Sargeant gets things underway with a 16.529, however, the American subsequently slips down the timesheet as almost everyone gores quicker.

Perez posts a 13.914 on the softs, but his teammate responds with a 13.664.

Hamilton goes third, ahead of Russell, Bottas, Alonso, Norris and Stroll.

"Driveability is still not great," reports Hamilton.

Just as Hulkenberg reports "drops of rain" on his visor, Sargeant goes off at the final corner and into the barrier.

The session is red-flagged.

That's a pretty wide run-off, and other than skimming right across the gravel on his way to the gravel the car is pretty much beached. "I'm sorry, I'm sorry," he sighs, the replay revealing the American suffered a snap midway through the corner.

As the car is removed from the gravel, it's: Verstappen, Perez, Hamilton, Sainz, Alonso, Russell, Leclerc, Bottas, Tsunoda and Norris.

The session resumes but as thunder rumbles in the distance, and a light drizzle falls, the teams wisely opt to wait and see how things develop.

With 40 minutes remaining, the rain duly increases in intensity.

With 28 minutes remaining, Norris breaks the deadlock, the youngster heading out on Inters.

A number of moments, including running wide at Turn 10, the McLaren driver wisely heads back to the pits.

Eventually, with 20 minutes remaining, the Ferrari pair head out, much to the delight of the fans. Both are on Inters.

As the Maranello pair continue, they are joined by Norris, Piastri, Ocon and Magnussen, all on the green-banded rubber.

"It's definitely raining," reports Russell, "the track just doesn't seem that wet."

All bar Hamilton, Alonso and Bottas are on track as Leclerc pits. Indeed, Hamilton is out of his car and showing no sign of going out anytime soon.

His Inters having "gone off", Norris thinks that now might be the time to make the switch to slicks.

Indeed, as Alonso and Bottas head out he is the only driver - other than Sargeant - not on track.

"The fronts are... I see rubber going off everywhere," reports Ocon.

Stroll goes off at Turn 5, the Canadian subsequently told to pit so that his floor can be checked.

Norris makes the switch to softs. And while it is a nervous lap it is faster than his pace on Inters. Nonetheless he isn't happy. "What the **** is wrong with the brakes?" he demands.

Sainz and de Vries also make the switch as Gasly goes off at Turn 3, much to the delight of the partisan fans.

Norris improves from a 1:21 to 1:19 as Leclerc gets down to a 1:17.

"F***, Mama mia!" declares de Vries as he almost collects Stroll as the Canadian exits the pits.

Hamilton has gone back out as Verstappen says he is unwilling to take any risks in pushing the car. "I don't feel comfortable pushing in these conditions, I think it's a waste." Tod that everyone else is pushing, he replies: "I don't give a f*** if everyone else is pushing, it just doesn't make sense!"

Meanwhile, Sainz is under investigation for impeding de Vries.

The session ends. Verstappen is quickest, ahead of Perez, Hamilton, Sainz, Alonso, Russell, Leclerc, Bottas, Tsunoda and Norris.

Zhou is eleventh, ahead of de Vries, Stroll, Hulkenberg, Piastri, Ocon, Magnussen, Gasly, Albon and Sargeant.

Check out our Saturday gallery from Barcelona here.