FIA Poised to Issue Austin Heat Hazard as Drivers Resist Cooling Vest Mandate

Singapore's first heat‑hazard weekend exposed limits of the new vest under an optional rule with a ballast penalty.

Overview

Forecasts for the United States GP point to 32–33°C, making a second consecutive warning likely under the FIA’s 31°C threshold.
When a heat hazard is declared, drivers may use the fluid‑cooled vest or accept 0.5 kg of cockpit ballast if they opt out.
Singapore’s debut brought mixed reviews, with several drivers saying the vest cooled for only 10–20 minutes and others reporting benefits for about 45 minutes.
Lewis Hamilton and Max Verstappen oppose making the vest compulsory, as the FIA has signaled a 2026 mandate that remains under discussion.
The measures were developed after heat‑related medical issues at the 2023 Qatar GP, with early trials highlighting cockpit packaging and comfort trade‑offs.