As well as the humidity, the drivers also look likely to get their first taste of wet running in 2012, with thunderstorms forecast for the whole week and looking increasingly likely to hit the weekend's feature and sprint races as well. Not that this was putting off an excited Berthon, of course.
"This is exciting as the bigger the challenge, the bigger the satisfaction when you succeed," he smiled. "I think my expectations are the same as those of all my competitors, if you race; you do so because you want to win."
Berthon was nonetheless trying to stay realistic in his expectations for his GP2 Series début.
"It's important to keep in mind that most of the GP2 drivers in 2012 have a lot of experience in this category already," he admitted. "This means they have some advantage at the beginning of the season. But the cards are in my hands and I will work very hard to reduce this advantage that more experienced drivers might have.
Racing Engineering clearly hope to be at or very close to the top when action starts at Sepang, but they won't know for certain until they get to see the relative strengths of their rivals. Right now, they're not sure who their main threats are going to turn out to be.
"This is always difficult to predict in GP2," said Leimer. "It also depends a lot on the team and how it is set up compared to the previous season. But I don't think there will be big changes from last year to this season."
So far the pre-season tests were dominated by DAMS' Davide Valsecchi at Jerez, and then by Lotus GP's Esteban Gutierrez at Barcelona, but teams were generally following their own development strategies and opting for race simulations over qualifying runs, leaving Racing Engineering generally running consistently around the midfield with both of their drivers.
But the first true test will come on Friday, with practice at noon local time (4am GMT) and then the all-important first qualifying session of the year at 3.55pm local time (7.55am). Only then will Leimer, Berthon and the rest of the GP2 field start to a get a real picture of how things genuinely stand heading into the 2012 season.
Live coverage of all GP2 practice, qualifying and race sessions is being shown on the new Sky Sports F1 channel this weekend.