@PotomacBobAccording to my research a CME (Coronal Mass Ejection) would not actually "hit" Earth. Some of the effects would interact with the Earth's atmosphere, electrical field, magnetic field, etc.
It would depend upon the time the event occurred, and in the 21st century we should have a fairly accurate estimation of when it would begin effecting out atmosphere and technological works. How powerful the event would determine a multitude of factors.
Some mitigation should be possible. Most of what we Need to do has to be begun years, decades even, before the event.
So much of what might happen is theoretical. The Earth's orbit is somewhat elliptical; some years we are a bit further from the sun than others. Depending upon the time of the year there is a variance of the axial tilt (resulting in winter in the northern hemisphere, and summer in the southern). Depending upon the power of the event, that may, or may not matter.
During the Carrington Event, it is reported that some telegraph lines, and other electrical devices Melted! Of course, they would melt under electrical loads routinely carried over lines in the 1940's, let alone the 21st century.
While politicians around the world have been seemingly oblivious, verging on negligent about the dangers of a EMP/CME. My research indicates that some measures have been enacted, often for other reasons, that might mitigate some of the worst effects. Of course, that depends upon how powerful the event is.
There is some speculation that "preparing for an massive EMP/CME attack is cost prohibitive" or that the masses won't survive to inflict consequences, and the "elites" will have "safe havens" it can be murky. Electrical infrastructure is often a national secret, even in the USA. NATO attacks upon the Serbian electrical grid in the 90's, as well as USA and coalition forces attacks upon the Iraqi grid, resulted in many nations, and some other entities, taking discreet measures to "harden" their grids, and some devices.
In a fiction story you have quite a bit of latitude.