Do solar flares change weather?
Solar flares cause the auroras commonly seen at the poles, but not much else.
Solar flares have little effect on weather because of Earth's magnetic field.
Earth's Magnetic Field
Auroras are caused to the collision of photons with particles in the atmosphere. The photons are able to interact with the atmosphere because of the increased velocity due to the photon's alignment of the magnetic field.
The other interaction that can occur comes after a solar flare, the Coronal mass ejection (CME). A CME is a massive amount of photons ejected from the Sun's corona. If the CME hits Earth's magnetic field it with cause a geomagnetic storm and generally weakens the magnetic field.
The effects of a geomagnetic storm include major damage to satellites, disruption to radios, damage to most electronics, and power outages.
Schematic of Coronal mass ejection