A 15-minute delay to the start of qualifying, owed to clearing the track of debris, meant Q3 ran late. That allowed for a storm to arrive in the closing stages of the shootout.
As a result, Q3 was ultimately red-flagged with four minutes to run when the thunder and lightning hit.
Max Verstappen therefore bagged pole for the Sunday race with a 1min10.727s flying lap set early in the session. The Red Bull driver pipped Leclerc by 0.294s, but both called out their messy laps as they felt grip levels vanished even without rain.
As clouds arrived overhead to plunge the track into darkness, wind levels increased to destabilise the cars. That created conditions Leclerc had never previously experienced and left him to consider binning his hot lap.
He said: "To be honest, today was, in my whole career, I've never experienced something like that. From Turn 4 onwards there was no rain. But the car was extremely difficult to drive - no grip.
"I was thinking about just coming in at the end of the lap. Then I finished and then P2, so it's a really good surprise. But it's a very weird one for everybody out on track today."
He added: "In those sprint weekends, there's always a big question mark on the race pace. But I hope it will be a good one.
"Hopefully there won't be too much rain tomorrow [for the sprint race] and Sunday.
Three-time world champion Verstappen called out the "insane weather" that he reckoned led to a "terrible" lap.
He said: "We didn't know when [rain] would hit in qualifying but we thought it would hit.
"But this is, of course, insane weather. Charles and I were just discussing our laps, they felt terrible.
"I think the wind started to change and started to be very strong. We lost a lot of lap time because of it. It was all quite hectic in the last lap."
"It seems that is all very close. You can see that already in qualifying.
"I expect the same also in the race around here - there is always quite a lot of [degradation] from the tyres. So, it's all about that management."
