Most Shocking State Result (4 years before each election)

[One Term Floridian]

1932: MN votes Democratic for the first time ever, and by 23 points
1936: Despite the continuance of the Dust Bowl, FDR still managed to win every state within the Great Plains, and against the Governor of Kansas nonetheless
1940: ME's strong swing towards FDR, despite being 1 of the 2 states he never managed to carry
1944: FDR's margins significantly reduced in the Upper South, with margins within the single digits in WV, KY and MO (despite Truman being on the ticket) and the Republican nearing 40% in VA and TN
1948: VA within single digits
1952: TX goes from being the Dems' best state to one of their worst performing states in the South
1956: MO votes for the Democrat in a GOP landslide
1960: The Deep South swings hard towards the GOP despite a southerner being on the Dem ticket
1964: VT votes Dem for the first time ever, and by 33 points for a southerner nonetheless
1968: SC chooses the GOP over the Dixiecrats
1972: The Dems do decently well in NYC's boroughs while getting blown out elsewhere in the state
1976: A southern Democrat nearly loses MS to a northerner and actually loses VA
1980: Same southern Democrat gets annihilated...in the South and elsewhere
1984: MN remains Democratic in a 49 state GOP sweep, despite being within 4% four years ago
1988: IA votes Dem by double digits in a 40 state GOP sweep
1992: Ticket with two southern Dems comes within single digits of carrying WY yet lose most of the former Confederacy to the GOP
1996: Uneven swing in the South, with both Dem candidates' home states swinging R (esp TN) and states like FL, WV, LA and VA swinging sharply towards them
2000: WV goes R against a southern Dem and by over 6 points nonetheless
2004: OH votes more Democratic than the rest of the country in a losing year for that party
2008: IN
2012: All-county GOP sweep in WV
2016: Dem has closest margin in UT in over 50 years yet the GOP candidate still wins the election with over 300 electoral votes

[One Term Floridian]

1964: I don’t think anyone In 1960 would think the Deep South would flip by 64

Not all that surprising in hindsight, especially seeing how strongly it swung towards a losing GOP candidate in 1960 despite having a southerner on the Dem ticket. Granted, I don't think anyone would have guessed that the Republican would be getting 87% in MS!

[One Term Floridian]

In 1984, TN was more Democratic than the nation as a whole. I guess Al Gore's reverse coattails and Carter's residual Southern strength played a big role. In 1996 NJ went from a small Clinton win in 1992 which was to the right of the national average, to a Clinton landslide in 1996.

Gore winning all counties, including eastern ones like Sevier probably helped lift Mondale quite a bit down there. This overperformance explains why TN was the only state to swing R in 1988. As for NJ, one could argue Perot took more Clinton's "need for change of leadership" votes up there as well as residual suburban strength for the GOP that was still around 4 years after the Willie Horton attack ads.

[One Term Floridian]

1948: Virginia
1952: Texas
1956: California (decent leftward movement)
1960: Arizona (was a D-leaning bellwether, and Ike was a good fit, but Nixon really won it by a lot)
1964: Georgia
1968: Maine
1972: Rhode Island
1976: Georgia
1980: Massachusetts
1984: Tennessee
1988: Iowa
1992: New Hampshire
1996: Arizona
2000: West Virginia
2004: New Mexico
2008: Indiana
2012: Missouri
2016: Utah

I think AZ swung heavily to the right following Goldwater's election to the Senate in 1952. In his re-election bid, he won by 13 points even as Dems gained a whopping 13 seats in the Sputnik midterm of 1958.