Abstract Geomagnetic substorms are a major path for energy storage and release in the magnetosphere, which typically occur in the midnight sector with a strong enhancement of westward electrojets. However, by analyzing 37,940 events from a substorm list, about 3% of events unexpectedly initiated in the noon sector. These dayside events occur more frequently during northern‐hemisphere summer and solar maximum years, and are predominantly associated with a strongly negative IMF By component, accompanied by a IMF southward turning shortly before enhanced westward electrojet. During these events, both westward electrojets and downward Region‐0 Field‐Aligned Currents (FACs) intensify near ∼80° MLAT on the dayside within 10 min after onset, with westward electrojets gradually drifting to the dawnside. We propose that these events are triggered by dayside reconnection during southward IMF conditions at high latitudes, thereby enhancing the convection electric field, downward FACs, and the westward electrojets.