The start of any new Formula One season is uncertain enough for teams and drivers without the addition of wet weather, which is expected for this year's opening Australian Grand Prix.
The forecast for Melbourne is for rain and possible thunderstorms from Friday through to race day on Sunday, which will render much of the best-laid preseason preparations and learned predictions irrelevant.
Throw in the always-slippery Melbourne street circuit, guessing games about the behavior of the new Pirelli tires, and uncertainty over how teams have adapted to the new rules, and this weekend's season opener appears about as unpredictable as any F1 race could be.
A wide-open race is precisely what the sport needs to start 2012, given the Sebastian Vettel procession last season, when the German driver set a record for the number of pole positions in a season and cruised to the title with four races to spare.
It would be a brave gamble to predict anything other than a Red Bull championship this season, as the team retains Vettel, able deputy Mark Webber, team principal Christian Horner and perhaps most importantly the most-lauded chief designer in F1, Adrian Newey.
It has been Newey's task to come up with a car that adapts to new regulations which prevent the channeling of exhaust fumes into the rear diffuser, supposedly reducing aerodynamic grip at the back end of the 2012 cars.
"It will be all the usual suspects, so I don't think there will be any surprise to see McLaren looking strong," Horner said when asked to nominate Red Bull's chief rivals for the season ahead.
"Ferrari are in better shape than people perceive. Mercedes look like they have made a bit of progress from last year, so it is going to be the usual protagonists up there."
Ferrari has had a troubled preseason testing period, and the Italian team's officials and head driver Fernando Alonso have candidly predicted struggles in the opening races of the season.
Last year it was McLaren which had the preseason woes, but preparations have been much smoother entering this year's first race, meaning Jenson Button and Lewis Hamilton figure to be the main challengers to Red Bull in Melbourne.
"The bad news is we don't look dominant, the good news is that no one else does either," team principal Martin Whitmarsh said. "Our sense it that we are competitive. The car seems quite reliable, the drivers like it and they seem to be quite buoyant."
Outside of the big three, Mercedes and Lotus appear to be the teams most likely to provide an upset at Albert Park.
Mercedes has failed to live up to expectations since becoming a team in its own right in 2010, and seven-time world champion Michael Schumacher has yet to even make a podium appearance since his return from retirement. But team chief Ross Brawn believes 2012 offers fresh hope of making up ground on the leaders.
"It is the quality of the field and the fact that the cars look like they are going to be close this year, it is going to be a really exciting season and it could be one of the best seasons we have seen for a number of years," Brawn said.
Lotus' renewed energy stems largely from the recruitment of former McLaren and Ferrari ace Kimi Raikkonen, who is back from a stint in rally racing, making it an unprecedented six world champions who will line up on the grid in Melbourne.
The Finn said "nobody knows" how any team will perform in the season opener, given the notorious unreliability of preseason testing times, but thought the Lotus was well suited to the peculiar challenges of Melbourne - a track that is very tough on brakes.
"You need a car with good traction and everything from testing says that the E20 has good traction so that will help us," Raikkonen said. "Strong turn-in and stable braking help too, and those areas also feel good with the car so we are well placed."
The driver lineups for the top four teams - Red Bull, McLaren, Ferrari and Mercedes - remain unchanged from last season, but there have been many changes elsewhere.
Raikkonen has been joined at Lotus by last year's GP2 champion Romain Grosjean, who had a brief spell in F1 with Renault in 2009. Former Williams driver Nico Hulkenberg steps up from reserve to fill a seat at Force India, replacing German compatriot Adrian Sutil, while Toro Rosso has an all-new combination of Australian Daniel Ricciardo - who moves over from HRT - and Frenchman Jean-Eric Vergne.
Bruno Senna replaces fellow Brazilian Rubens Barrichello at Williams, Russian Vitaly Petrov moves to Caterham at the expense of Jarno Trulli, Charles Pic joins Grosjean and Vergne in a trio of new French faces and will drive for Marussia, while HRT has gone for the veteran pairing of Pedro de la Rosa and Narain Karthikeyan.