Overview

• Race director Rui Marques notified teams on Thursday after the FIA forecast hit the 31°C threshold that triggers the heat regulations.
• Every car must have the Driver Cooling System fitted and operational, including a pump, fluid reservoir and heat exchanger mandated since the 2025 season start.
• Drivers may wear the cooled undershirt to use the system or run extra ballast if they decline the vest, a trade‑off teams are weighing for performance and comfort.
• Reactions vary: Lewis Hamilton criticized the garment’s comfort, Fernando Alonso said he expects to use it on Sunday, and Nico Hülkenberg endorsed the cooling for Singapore.
• The measures follow past heat‑related incidents and reflect Singapore’s strain with humidity near 80% and potential fluid losses of several liters despite limited in‑car drinks.