With forecasters predicting a 50 percent chance of rain, weather will be a key factor when Formula One stages its first ever night race Sunday under lights on the public streets of Singapore.

Because the race is at night, track temperature will likely be less than the air temperature, creating slippery conditions for the drivers on a circuit lined with metal barriers.

To the slick track, add tropical Singapore's heat, humidity and a 50 percent statistical chance of rain on any given day in September.

"These are difficult conditions to work in for both the team and the drivers, however it could lead to some very exciting on-track moments on a circuit which is lined with barriers," Honda team principal Ross Brawn said. "The weather will be a key factor in the weekend."

McLaren has said it will use coatings for visors that stop droplets of water collecting. But drivers will still have to contend with the glare or sparkle of lights reflecting off rain water.

"I don't think driving at night will be a problem if it's dry. But if it's wet, which it looks like it will be, it could be quite difficult with the reflection," Williams driver Kazuki Nakajima said.

Vijay Mallya, chairman of the Force India team, said that after living in Singapore for the last 25 years he knows to expect rain on Sunday.

"It rains every night," he said. "You don't have to pray for rain, it just comes."

Singapore, the fifth and final street circuit on this year's F1 calendar, is made up almost entirely of public roads, running 5.067 km around the city-state's picturesque Marina Bay for the 61-lap race.

One of only three races this year to run in an anti-clockwise direction, it will be lit by 1,500 light projectors with 2,000-watt halide lights spaced 4m apart. Standing 10m above the ground, they will generate light four times brighter than an average sports stadium.

With 23 corners, the circuit provides an abundance of first and second-gear bends that is expected to produce an average lap speed of just 175 kph, a speed similar to fellow street circuit Monaco.

The Singapore track has only a handful of high-speed stretches, including the Raffles Boulevard on which the drivers should reach a top speed of 308 kph.

"It will be a very unusual weekend from a sporting perspective," Renault's former world champion Fernando Alonso said.

Team officials say driving at night will not be a problem as long as the drivers' biological clock remains on Europe time and does not acclimatize to Singapore. Night time in Singapore will correspond to afternoon in Europe, a period when drivers are at their peak performance.

"Essentially we must not acclimatize to the local time, which is totally different to how we normally operate," championship leader Lewis Hamilton said.

With Saturday's qualifying not due to start until 10 pm local time (1400 GMT) and Sunday's race at 8 pm, managing the drivers' routines will be paramount.

Hamilton said drivers will be eating, waking and sleeping in European time.

"For example, we will get up early afternoon for breakfast, have supper at 1 am and go to bed at around 3 am. It will be very different preparation to any other race," the McLaren driver said.

To ensure undisturbed sleep for the drivers, hotel rooms will be blacked out, housekeeping staff will be told to stay away and telephones won't ring.

"We will essentially be isolated from the normal workings of the hotel," Hamilton's teammate Heikki Kovalainen said.

(Agencies via China Daily September 24, 2008)