Tropical cyclones (TCs) are generally recognized for their destructive impacts through strong winds and heavy precipitation, yet their remote atmospheric influences on coastal extreme heat remain poorly understood. In particular, some TCs can induce anomalously warm conditions over adjacent coastal regions through subsidence warming, clear-sky radiative forcing and suppressed sea breeze. Understanding why similar storms produce contrasting thermal responses is essential for improving the prediction of compound coastal climate extremes.
Here, we investigate the relationship between tropical cyclone characteristics and extreme hot days in Hong Kong during the historical period of 1884–2023. Combining long-term surface temperature observations, IBTrACS tropical cyclone records, and ERA5 atmospheric reanalysis, we find when TCs come to 85 1°×1° grid boxes east of HK, HK hot weather arises 4 times more likely. We also find TC-related hot weather strengthens and decays 30% faster than TC-unrelated hot weather, which is challenging for human and ecosystems to adapt. Composite analyses of geopotential height, sea-level pressure, lower-tropospheric circulation, and vertical velocity are used to quantify the atmospheric mechanisms associated with TC-induced warming. We further compare weak and strong TCs based on pressure-based intensity classifications and explore whether stronger storms produce enhanced temperature anomalies or distinct spatial patterns of coastal warming. By linking tropical cyclone intensity, atmospheric subsidence, and regional extreme heat responses, this study provides new insights into the atmospheric drivers of compound coastal extremes and highlights the importance of considering remote TC effects in future climate risk assessments.