If you're standing on a sweltering subway platform, you're not suffering in solitude. A new study tracking rider complaints across New York, Boston, and London found that underground heat discomfort has been rising in a clear, measurable way as outdoor temperatures climb.⁠ ⁠ Using more than 85,000 posts from X and Google Reviews published between 2008 and 2024, researchers identified over 22,000 complaints specifically tied to thermal discomfort in subway systems. Instead of relying on short surveys or scattered temperature checks, they used years of public posts to build a wider picture of how commuters actually experience heat below street level.⁠ ⁠ The trend was steep. For every 1°C increase above 10°C, complaints rose by 10% in Boston, 12% in New York, and 27% in London. Complaints peaked in summer, especially in July, and surged during major heatwave years like 2018 and 2019. In Boston and New York, riders complained most around noon and again near 9 p.m., while London peaked in t...