Ahead of today's second session the air temperature is 26 degrees C, while the track temperature is 38 degrees. As smog descends on nearby Mexico City, race control says there is a 20% chance of rain.

Having handed their cars over to the rookies earlier, this afternoon Russell, Magnussen, Bottas, Gasly and Tsunoda are back in their usual seats.

In terms of upgrades, Red Bull has new Cooling Louvres as does Ferrari and Alpine, which also has a new Engine Cover.

McLaren has a new Engine Cover and Front Corner, while Alfa Romeo has a new Rear Corner and Haas a new Front Corner Circuit and Cooling Louvres.

AlphaTauri brings a new Front Corner and Engine Cover, while Williams has a new Engine Cover and Cooling Louvres, nearly all of the upgrades being circuit specific.

As well as new drivers and new parts, this morning - and this afternoon - will also see new tyres as Pirelli runs a new prototype C4 (medium).

Verstappen was quickest earlier, but only 0.095s ahead of Albon, while local hero Perez was third.

Though a fairly straightforward session, Sainz encountered a hydraulics issue which cost him track time, while a brakes problem meant that Pourchaire failed to post a time. Though he handed his car over to Isack Hadjar, Tsunoda looks likely to start from the back of the grid on Sunday after taking on a new engine and gearbox.

The lights go green and Russell leads the way, followed by Stroll, Tsunoda, Gasly and Bottas.

As more drivers head out the majority are on the prototype rubber, though a coupe are on hards and two on mediums.

Russell gets things underway with a 21.618, though this is soon beaten by Ricciardo (20.568).

Zhou goes second, ahead of Alonso, but both are demoted when a 20.830 puts Sargeant second.

Leclerc goes quickest with a 20.394 though this is soon eclipsed by Norris (20.019).

Perez posts a 20.786 to go fourth.

"The rear appears to be braking pretty aggressively," reports Russell.

Albon goes second (20.358) as there are reports of rain in the pitlane.

Verstappen goes top with a 20.085, like Norris, Albon and Leclerc he is on the prototype rubber.

"It's raining here a little bit, I think," reports Verstappen.

Perez crosses the line at 20.752 but remains 8th as Norris gets all crossed up after hitting the kerbs.

Albon goes quickest with a 20.075.

"It's a struggle out here, there's no grip," says Hamilton. The Briton is currently 15th while his teammate is 8th.

Verstappen retakes the top spot with a 19.511 as Ricciardo goes second and Bottas third. All three on the prototype rubber.

Sainz (medium) goes third (19.832) but is demoted when his teammate posts 19.611 to go second.

Russell improves to sixth with a 20.047.

Quickest in S2, Bottas crosses the line at 19.865 to go fifth overall.

"The ride seems to have got a bit worse over the kerbs in sector one," reports Perez.

With 40 minutes remaining, Piastri makes an early switch to softs. Unsurprisingly, he goes quickest in the final two sectors, crossing the line at 19.163 to go top.

Albon, Alonso, Perez and Sargeant follow his example and switch to the red-banded rubber.

Though quickest in the opening sector, Albon can only manage a 19.446 to go second.

Alonso spins at Turn 10 but is soon on his way again.

Verstappen goes quickest with an 18.686, as Norris goes second and Ocon third.

Hulkenberg goes quickest in S1 as Hamilton (19.024) goes third overall. Hulkenberg finally crosses the line at 19.535 to go seventh, the Haas struggling in the twisty sections.

Perez goes third with an 18.988 as his teammate posts a 19.024 to go fifth.

"I went off in the last corner," admits Perez as Bottas goes third (18.955) only to be demoted by Leclerc.

As ever, the Aston Martin pair avoid the softs, while Piastri has switched to the hards.

"It's about 10 laps until expected rain," Alonso is warned, "10 or 12."

A big lock-up for Bottas as the Aston Martin crew do their best to prevent prying cameras getting a look at what's going on with Stroll's car, where his front-left tyre is seemingly stuck.

"It's raining again," reports Russell with 16 minutes remaining.

Attention has now switched to Sunday afternoon with the majority on mediums though a few are on hards.

Surprisingly, Sainz remains 0.571s off the pace, the Spaniard not having had the easiest of weekends thus far.

"The rain is picking up in the last sector," warns Perez.

With 9 minutes remaining, Stroll finally heads out again.

Leclerc takes a punishing ride over the kerbs at the chicane.

Albon is back in the garage after something appeared to break off of his car.

"I advise we don't continue," says Russell of the conditions, "relatively high risk, just for the sake of driving."

Indeed, as conditions worsen the majority of drivers pit. That said, most of them subsequently head back out again.

The session ends. Verstappen is quickest, ahead of Norris, Leclerc, Bottas, Perez, Ricciardo, Hamilton, Ocon, Piastri and Russell.

Sainz is eleventh, ahead of Tsunoda, Zhou, Albon, Hulkenberg, Gasly, Sargeant, Stroll, Magnussen and Alonso.

Check out our Friday gallery from Mexico City here.