A CA electoral college delegate represents the will of ~710,000 voters. A WY delegate represents the will of only ~200,000 voters, so a vote in WY counts more than 3x as much as a vote in CA. (For much the same reason, congress also sees disproportionate representation of smaller states, since the number of senators is fixed.)
Not to mention gerrymandering results in outsized influence of rural/urban boundaries as well.