BC in October of 1992. Can't find anything that says whether it was a day or night game though. They were also the underdog in that game given SU was the #10 team in the country.
Against Pitt in October of 1991. Can't tell if it was a night game.
I'll just list the top 25 opponents we beat on the road for our entire history, this is night or day games, because honestly the site I'm using doesn't give the time the game was played:
2010s
* 2010 - West Virginia-NOON
2000s
* 2007 - Louisville-NOON
* 2004 - Boston College-NOON
* 2001 - Virginia Tech-NOON
1990s
* 1998 - Michigan-330
* 1996 - West Virginia
* 1995 - UNC-7pm
* 1992 - West Virginia
* 1992 - Boston College
* 1991 - Pittsburgh
1980s
* We didn't beat one ranked team on the road.
1970s
* We didn't beat one ranked team on the road.
1960s
* 1967 - UCLA
* 1960 - Kansas
1950s
* 1959 - Penn State
* 1959 - UCLA
* 1956 - Maryland
* 1955 - Army
* 1955 - Holy Cross
* 1955 - West Virginia
1940s
* 1940 - Columbia
1930s
* We didn't beat one ranked team on the road.
1920s
*1924 - Penn State (Richard Billingsley rankings from here on out).
*1923 - Nebraska
Teens
*1919 - Army
*1917 - Nebraska
So from 1897 to 1991 we beat 13 ranked teams on the road. In our entire history. That's crazy.
From 1991 to present day we've beaten 10 ranked teams on the road. So we've beaten 23 ranked teams on the road in our entire history. We also went from 1967 to 1991 without a win against a ranked team on the road.