The start time of the Miami Grand Prix has been brought forward by three hours due to the threat of thunderstorms.
Lights out is now scheduled for 18:00 BST (13:00 local time) and reigning world champion Lando Norris is unsure how much the expected wet conditions will impact the cars, following one of the biggest rule changes in the history of the sport.
There is now a huge amount of electrical power available in the new engines and some teams have struggled to deploy it in a predictable way.
"I don't know how wet it's going to be," Norris said.
"It's going to be a big challenge on race day for everyone to perform, find the limit. Obviously, you can't afford to make any mistakes. We're thrown in the deep end, but that's what we're here to do. I look forward to it."
The Briton will start from fourth on the grid, behind Kimi Antonelli, Red Bull's Max Verstappen and Ferrari's Charles Leclerc.
Both F1 and the FIA (the governing body) came to the decision to alter the start time on Saturday evening, citing "heavier rainstorms" that are predicted to arrive close to the original 21:00 BST start time.
"This decision has been taken to ensure the least amount of disruption to the race, and to ensure the maximum possible window to complete the grand prix in the best conditions and to prioritise the safety of drivers, fans, teams and staff," read a statement released jointly by F1 and the FIA.
With the beginning of the race being brought forward, it is hoped that the worst of the weather will arrive later, resulting in minimal disruption to the event.
The heavy rain is forecast to set in for hours once it begins and if there would be significant threat to the race going ahead if they continued with the original start time.
Antonelli (6/5) is set to start as favourite with Verstappen (11/4) and Leclerc (9/2) not too far behind him in the market.
Any odds displayed were correct at the time of writing and are subject to fluctuation.
