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Solar geoengineering that aims to offset global warming could nonetheless alter atmospheric temperature gradients and humidity and thus affect the extratropical storm tracks. Here, we first analyze climate model simulations from experiment G1 of the Geoengineering Model Intercomparison Project, in which a reduction in incoming solar radiation balances a quadrupling of CO2. The Northern Hemisphere extratropical storm track weakens by a comparable amount in G1 as it does for increased CO2 only. The Southern Hemisphere storm track also weakens in G1, in contrast to a strengthening and poleward shift for increased CO2. Using mean available potential energy, we show that the changes in zonal‐mean temperature and humidity are sufficient to explain the different responses of storm‐track intensity. We also demonstrate similar weakening in a more complex geoengineering scenario. Our results offer insight into how geoengineering affects storm tracks, highlighting the potential for geoengineering to induce novel climate changes. Plain Language Summary: Solar geoengineering refers to reflecting incoming sunlight to counteract the greenhouse effect of increased carbon dioxide concentrations and is one proposed intervention to avoid the most dramatic risks of global warming. Climate under solar geoengineering would nonetheless be meaningfully different from a baseline climate without increased carbon dioxide. The extratropical storm tracks, regions with heightened incidence of extratropical cyclones, are important components of weather and climate outside of the tropics. In simulations with global climate models, we find that the storm track in the Northern Hemisphere is similarly weakened in a solar geoengineering scenario with little change in global mean temperature as in a global warming scenario. The storm track in the Southern Hemisphere also weakens in the geoengineering scenario in contrast to a strengthening with global warming. The weakening of the storm tracks in the geoengineering scenario is partly related to a weakening of the pole‐to‐equator temperature gradient in both hemispheres. This means that reflecting incoming sunlight may not prevent changes in the strength of extratropical cyclones in the Northern Hemisphere and may overcorrect in the Southern Hemisphere. Key Points: Northern Hemisphere extratropical storm track weakens in response to increased CO2 even with the use of solar geoengineeringSouthern Hemisphere extratropical storm track also weakens in a solar geoengineering scenario but strengthens under global warmingStorm‐track intensity changes in all cases are related to changes in mean temperature structure and moisture [ABSTRACT FROM AUTHOR]