The Ithaca Police Department FAQ states:
"Effective November 1 through April 1 of each year no person shall park a vehicle between 2:00 A.M. and 6:00 A.M. on the odd-numbered side of all City streets on the odd-numbered days of the calendar month, and on the even-numbered side of all city streets on the even-numbered days of the calendar month." (emphasis added)
In practice, this generally means that in the evening one should park on the even side of the street on even-numbered days, and the odd side of the street on odd-numbered days. (Because enforcement of the rule will occur in the early morning hours of the following day.)
However, there are three cases where this rule of thumb does not work and can lead to confusion:
When in doubt, stop on by whichsidetopark.info and have a computer figure it out for you!