Sepang forecast worsens as F1 faces 75% rain risk and a heat problem for 2026 engines

The Bahrain Grand Prix in Malaysia runs from Friday 2 October to Sunday 4 October. It is F1's first race at the Malaysian circuit since 2017.

GPblog already looked at the chance of rain in F1 drivers to face new challenge according to Malaysia weather forecast. The latest numbers point higher, and the heat has become a story of its own.

Rain is forecast on all three days of the event. Sunday currently shows a 75% chance of afternoon rain and an estimated 3.6mm of precipitation and the the 56-lap race starts at 15:00 local time.

Friday also carries a 75% chance of rain in that forecast, and the risk continues into Saturday's final practice and qualifying. Air temperatures could reach 33°C, while relative humidity of around 73% is expected to push the feels-like temperature to 43°C.

Rain is only half of the story as the heat is the real challenge for the new generation of cars.

Under the new regulations, a hot battery means less electrical deployment. Drivers would therefore have less energy to use on Sepang's two long straights, which are the circuit's main overtaking zones.

The heat is also a matter of driver welfare and cockpit temperatures at Sepang could sit between 40°C and 50°C, with track temperatures reaching 60°C.

This is where the rain and the heat collide as cooling configurations are locked at qualifying under parc fermé, so a team that guesses wrong on Saturday could watch its engine derate on Sunday.

That leaves teams with a trade-off. If a team sets up its cooling for a hot, dry race and the forecast afternoon storm arrives, it is stuck with that choice. If it bets on cooler, wet conditions and Sunday stays dry and humid, the battery could overheat and electrical performance would drop.