The FIA has banned full electric boost in wet or low-grip conditions for the Miami Grand Prix under Article B7.2.1g (FIA-F1-DOC-058), citing safety concerns with the new hybrid power units. The rule will be applied during the Miami weekend if heavy rain or low-grip conditions materialize, and the FIA said the immediate, weather-triggered measure did not require the usual route through the F1 Commission; teams were reported to have backed broader regulatory tweaks.

The ban prevents drivers from using full boost mode in the wet, which the FIA’s text says stops access to what had been up to about 350 kW of additional electrical power. To avoid confusion between figures cited in different sources, the 350 kW figure refers to the maximum super-clipping potential; an earlier and agreed package includes a race boost cap of roughly +150 kW and a cut in qualifying energy-harvesting from 8 MJ to 7 MJ. Some reports also referenced alternative wet-power numbers around 250 kW, and the published documents separate the immediate wet-condition prohibition from the wider technical limits in the regulatory package.

Operationally, the wet ban inhibits boost mode while leaving pre-programmed electrical deployment maps active, a compromise intended to smooth torque delivery but one that could still produce meaningful speed differences between cars. Straightline-mode rules were tightened, Driver Adjustable Bodywork (DAB) will be allowed only for partial activation in designated low-grip zones, and rear wings are to remain in a fixed closed configuration to preserve rear stability and reduce sudden front-drag changes. The broader package also includes an automatic MGU-K start-assist to reduce grid-start risks.

The changes follow limited wet running in Barcelona, where teams and drivers reported the new power units delivered instant torque that made cars prone to oversteer and produced unpredictable behavior on corner exit and under acceleration in the wet. Heavy rain forecasts gave urgency to the measures, with reported thunderstorm probabilities for Sunday between about 68 percent and 85 percent, and U.S. lightning safety protocols could force delays, stoppages or red-flag interruptions. Teams and drivers met with the FIA to discuss possible schedule adjustments, including an earlier race start, and organizers said contingency plans and shelter would be available inside Hard Rock Stadium and in the team garages. Drivers warned of difficult and counterintuitive wet running with the new cars, and Charles Leclerc said low visibility, divergent power-unit strategies and the need to stay flat-out could leave drivers feeling like “passengers.” Other concerns included difficulty heating tires in the wet, unproven intermediate tires, the Miami track’s poor drainage and standing water, and the risk that removing the wet boost option could expose engine performance differentials among manufacturers. Teams, officials and fans will watch both the weather and the technical implications closely throughout the Miami weekend.