Ahead of today's second practice session, the air temperature is 24.3 degrees C, while the track temperature is 26.3 degrees.
George Russell topped the timesheets earlier, ahead of Red Bull's Max Verstappen and Alex Albon. Valtteri Bottas was fourth, the Finn's efforts compromised by floor damage incurred early in the session.
However, Toto Wolff was keen to make clear that both his drivers were on similar programmes and running similar fuel loads.
Behind the leading quartet were the two AlphaTauris, followed by Ocon, Vettel, Ricciardo and Leclerc. The Points were 11th and 12th and the McLarens 13th and 16th.
Ahead of this afternoon's session the FIA has announced that drivers who exceed track limits at Turn 8 will be punished. The corner witnessed a number of incidents earlier.
Talking of incidents, F2 qualifying demonstrated that traffic is going to be a problem here, with Mick Schumacher set to start at the rear of the grid following a coming together with another driver.
The lights go green and Fittipaldi is first out, the Brazilian sporting mediums.
The Haas driver crosses the line at 57.855 to get the session underway.
As he improves to 56.949, Fittipaldi is joined by the Alfa Romeo pair.
Raikkonen posts 56.082 and Giovinazzi 56.130 as the McLaren pair head out.
A 55.679 sees Stroll go top, only to be demoted when his teammate crosses the line at 55.668. Sainz goes third and Norris fourth.
Ocon stops the clock at 55.210 as Raikkonen has a nasty wobble and Aitken almost comes to grief as he comes upon a much slower car (Magnussen) on the racing line in Turn 6.
Sainz has the dubious honour of being the first driver to have his time deleted.
A spin for Vettel in Turn 2 after going a little too wide in Turn 1.
Having gone quickest in S1, Leclerc backs off in the second sector after finding himself behind Ocon. Qualifying is going to be a nightmare.
Ironically, Ocon goes quickest (55.185), ahead of Perez, Gasly, Ricciardo and Stroll.
Leclerc has a gearbox issue and despite his concern that he will not make it back to the garage, as he is stuck in sixth, he does.
While almost all the times up until now have been posted on mediums, on hards Russell posts a 55.675 to go sixth.
"I've got some damage to the floor," reports Norris, "some bits just flew off."
Bottas runs over the kerb in the final corner, and replays suggest it hasn't done his Mercedes any good, raising fears that the kerbs are going to be an issue this weekend.
The Finn goes third (55.321), just moments after Verstappen raised the bar with a 55.043.
In the Ferrari garage, Leclerc's car is up on its stand, his session seemingly over.
Albon goes fourth with a 55.335, 0.292s down on his teammate.
Andreas Seidl reveals that as feared Norris has incurred damage following his encounter with those unforgiving kerbs.
Another spin for Vettel, the German lucky not to collect Magnussen after passing on the approach to Turn 5.
Switching to the softs, Perez goes quickest with a 54.866 as Kvyat goes third (55.090) and Stroll fourth (55.104).
Quickest in the opening sector, though hampered by traffic further around the lap, Ocon still manages second with a 54.940.
"I find it difficult just to make it around," says Vettel, "I nearly lost the rear again."
A PB in S1 is followed by a purple as Bottas posts a 54.506 to go quickest.
Next up is Russell, who, like his teammate, is on fresh softs. A PB in S1 is followed by another, as Bottas' time is deleted. Russell crosses the line at 54.713, 0.2s slower than Bottas but legal.
Verstappen aborts his first flying lap, while Albon goes fifth with a 55.036.
Verstappen subsequently improves to 54.869, which is only good enough for third. The Dutchman and his teammate both complain of "much oversteer".
Bottas has aborted three successive flaying laps. It is not going well for the Finn, while his teammate is currently quickest.
At the end of the qualifying sims, Russell is quickest, ahead of Perez, Verstappen, Ocon, Albon, Kvyat, Stroll, Ricciardo, Gasly and Sainz.
Ferrari reports a "driveshaft issue" on Leclerc's car, as Norris, who has just headed out again, reports an issue and heads straight back to the pits.
The long runs get underway.
More problems for McLaren, as Sainz reports "I lost synchronisation on the gears". The Spaniard slowly makes his way back to the pits.
"There is no answer, I have nowhere near the grip I need," says Vettel.
Trackside coverage from Turn 8 reveals a number of drivers are still exceeding the track limits.
Vettel is still having trouble remaining on the black stuff, the German having to use the generous run-off at Turn 7. Bottas also struggling still, the Finn locking-up in Turn 1.
Aitken has completed the most laps (48), ahead of Kvyat and Giovinazzi (47). Leclerc has completed just 2 laps and Norris 14.
Another big lock-up followed by a filling-rattling ride over the kerbs for Bottas who is having a torrid time of it here.
"Im-poss-ible to pass," sighs Verstappen.
"Ahhh, I took gravel on my finger," says Gasly, the culprit of said gravel dumping being a certain V Bottas.
On the longer runs on hards, the Red Bulls appears to have the edge.
The session ends. Russell is quickest, ahead of Verstappen, Perez, Ocon, Albon, Kvyat, Stroll, Ricciardo, Gasly and Sainz.
Bottas is eleventh, ahead of Raikkonen, Giovinazzi, Magnussen, Latifi, Vettel, Norris, Fittipaldi, Aitken and Leclerc.
An interesting session, and while Russel will , quite rightly dominate the headlines, Renault and AlphaTauri have both looked strong, while Sergio Perez came to life again.
On the other hand Ferrari clearly has issues, while McLaren has yet to convince.
And then there's Valtteri who appears to be having one of 'those' weekends.
Check out our Friday gallery from Bahrain, here.