Abstract: A clear understanding of the temporal–spatial distribution, circulation patterns, and environmental conditions of thunderstorm high winds (THWs) is essential for improving the accuracy of forecasting and warnings. Using THWs observations from national and automatic weather stations during 2015–2021, this study applied strict quality-control procedures to analyze the temporal and spatial characteristics and circulation patterns of THWs across China. In addition, the dominant weather regimes of THWs were objectively classified through the Empirical Orthogonal Function (EOF) analysis of the 500 hPa geopotential height field, followed by K-means clustering, and the associated environmental conditions were further investigated. Results show that (1) North China and Northeast China, the Jiangnan region and South China region, the northwest part of Xinjiang, and the plateau region are the four THWs high-frequency regions (hereafter called Regions 1–4, respectively). THWs occur earliest in Region 2. The highest frequency of THWs was in June. (2) Four circulation patterns are identified in Regions 1 and 3, while five patterns are identified in Regions 2 and 4. Region 1 is typically influenced by cold vortices on the upper levels and significant vortices and cold–warm confrontations on the lower levels, with the one-trough-and-one-ridge circulation being the most frequent (30.4%). Region 2 is affected by various circulation configurations, such as the Southern trough, eastern wave, East Asian trough, and intertropical convergence zone. The strong West Pacific subtropical high-alignment low-level convergence zone occurs most frequently (27%). The typical circulation patterns of THWs in Region 3 are characterized by west wind trough fluctuations (proportion: 52.4%). The South Asian High accounts for the highest proportion (52.7%) in Region 4. The upper trough is another major circulation that produces THWs in the plateau region. (3) There are significant differences in the thermal dynamic conditions for generating THWs across different regions. Region 3 is dominated by dry THWs, whereas Region 2 is dominated by wet THWs. Regions 1 and 4 are dominated by dry THWs. In Region 1, dry THWs closely related to cold vortices feature low convective available potential energy (CAPE) and strong wind shear conditions. In contrast, wet THWs related to the peripheral subtropical high in Region 2 and the South Asian high in Region 4 exhibit high CAPE and weak wind shear conditions. These findings provide a solid reference for understanding and forecasting THWs in different regions in terms of circulations and environmental conditions.