Ahead of today's second practice session, the air temperature is 34 degrees C, while the track temperature is 60 degrees. It is hot, so hot, with humidity currently 47%. However, there are some ominous dark clouds in the distance.

As a reminder, in terms of upgrades, McLaren has a new Coke/Engine. To meet the high cooling demands of this and other upcoming circuits, this revised engine cover is aimed at increasing cooling massflow.

Red Bull has a new Floor Board. Applied above the existing floor foot geometry, this new board realises development work to extract more load locally whilst maintaining flow stability behind the front tyres.

Ferrari has a new Diffuser. However, this is not Sepang specific, however the very localized development around the diffuser winglet cascade provides a favourable additional downforce across the entire car operating envelope.

Racing Bulls have a new Front Wing and Rear Wing. A longer chord flap for the front wing that was introduced at Baku increases the load that can be generated by the wing, thereby meeting the aero balance requirements for this circuit, while an improved design of the rear wing support components allows the rear wing to perform more effectively, increasing the efficiency of load generated.

Haas has a new Rear Impact Structure. This additional rear impact structure device will enable targeted tuning of the car's characteristics for this circuit. Alpine has a new Front Corner. The front drum exit has been trimmed to increase brake cooling capacity, thereby improving thermal management for the upcoming high-demand tracks.

Other than a revised livery, in honour of partner Petronas, this weekend sees Mercedes introduce its much-anticipated - and much-feared, no doubt - upgrade. This includes a new Floor Board, Floor Leading Edge, Floor Corner, Floor Body, Rear Suspension, Rear Corner and Rear Bodywork. On the floor board, reprofiled elements and new vertical elements have been added to improve local pressure distribution, reduce separations at the extremes of the operating envelope, and improve flow to the rear of the car, resulting in increased load, while additional down-washing elements increase local load and outwash, improving flow to the rear of the car and increasing rear floor load. Re-optimisation of floor corner slot arrangement is to both increase local load and also improve flow into the diffuser and hence rear load, while through re-optimisation of the diffuser roof and sidewall the German team has increased local load and improved robustness throughout the operating envelope. In terms of the rear suspension, track rod and driveshaft camber has been re-distributed in order to increase local load whilst improving coupling with the diffuser winglet and rear drum furniture, while the chord and position of the rear drum winglets have been re-optimised to work with the fairing update and to improve rear tyre wake control across the operating envelope. Finally, the revised rear bodywork, with its reduced volume and increased sideview ramp, increases downwash to the rear floor and rear drum, resulting in more load.

Verstappen was quickest earlier, ahead of Russell, Hadjar, Leclerc, Antonelli, Hamilton and Gasly.

Just 10 of the current drivers have ever driven here before, however almost everyone was impressed with the track, despite the heat, the dust, the lack of grip and tyre deg.

Other than his 5-place grid penalty for his Baku-bash, Colapinto has a further 10-place penalty for taking on new engine components, while Hadjar has a 5-place drop for the same and Lindblad a whopping 30-place hit!

Green light, and with an eye on those dark clouds the drivers are keen to get to work. Ocon leads the way, followed by Bearman, Hulkenberg, Lindblad and Sainz.

Among those eager to get to work are the McLaren pair, who are now both running the Macarena wing.

Most are on mediums though a few, including Gasly the McLarens, who are on softs.

Gasly is warned that the rain shower might be "disruptive", which is likely to prove an understatement.

Russell is told that the rain will arrive at Turn 7 first.

Lindblad posts a benchmark 38.880, but Gasly and then Hamilton respond with a 38.577.

All 22 drivers are on track.

A 38.020 from Russell, as Antonelli stops the clock at 38.060.

Verstappen goes top with a 37.785, as Leclerc goes third.

In a bid to keep tyre temperatures to a minimum - the opposite of what was saw last week - drivers are crawling around the twisty sections of the track.

"On the entries the car is bouncing like..." warns Hadjar as Verstappen insists that every time he is in his car the seat is in a different position. "It's just a lottery of how I sit in the car," he sighs. "I don't know why."

Currently sixth, 0.892s off the pace, Gasly is highest placed soft runner.

Lindblad runs wide in Turn 6 and Gasly at Turn 7.

15 minutes into the session, Russell switches to softs, as does his teammate and the Ferrari pair.

Though quickest in the second sector, and being on the red-banded rubber, Antonelli remains fourth.

Ocon runs wide and takes a bumpy ride over the serrated kerb.

Quickest in S3, Leclerc goes top with a 37.528, as Hamilton goes third. However, the Briton is demoted when Norris goes second with a 37.665.

"What is this guy doing, man," asks Bortoleto of Hamilton who is dawdling on the racing line.

The incident has been noted.

"I can't see through my right mirror," says Hamilton.

While Verstappen has yet to run the softs, teammate Hadjar goes second (37.627) on the red-banded rubber.

Colapinto, currently 22nd, also has yet to run the red-banded rubber.

Attention turns to Sunday as Bortoleto runs wide and calls on his team to check his floor. Replay shows that he ran wide as a result of his active aero opening and catching him by surprise.

Talking of Sunday, Bortoleto is enjoying a great scrap with Lindblad.

The pair battle for a couple of laps, running side-by-side in several corners before the Brazilian gets ahead.

After a wild, wild lap, featuring lots and lots od understeer, Stroll heads into the pitlane and subsequently locks-up big time.

On their long runs, Russell is 1.2s off his teammate's pace despite brin on softs. The McLarens are showing good pace, albeit on the softs, as is Hadjar on the yellow-banded rubber.

A lock-up for Piastri in Turn 9, as Bortoleto stops at Turn 8.

The VSC is deployed as he reports a gearbox issue and climbs from his car.

Norris does well to avoid Perez as the Mexican brakes heavily as he enters the pitlane.

Despite the fact that a number of drivers posted their best times on the mediums, Verstappen was the only driver who didn't run the softs.

Leclerc is quickest, ahead of Hadjar, Norris, Verstappen, Hamilton, Piastri, Russell, Antonelli, Lawson and Gasly.

Lindblad is eleventh, ahead of Bortoleto, Hulkenberg, Ocon, Alonso, Bearman, Sainz, Stroll, Bottas, Albon, Perez and Colapinto.

As the drivers take their places on the grid for their practice starts, it is noticeable that their tyres have loads of little stones imbedded in them.

So, not for the first tmie, we were promised rain, but it never arrived.

That said, if that Bortoleto/Lindblad battle is any indication of what we might expect on Sunday, who cares?