The Congress adopted a uniform day on which the States were to choose their Electors in 1845, the Tuesday following the first Monday in November in years divisible by four.
Twenty First Century
Prior to 1845, Congress permitted the States to conduct their presidential elections (or otherwise to choose their Electors) anytime in a 34 day period before the first Wednesday of December which was the day set for the meeting of the Electors in their respective States.
Note: 1900 breaks the pattern because there was no leap day in 1900. Leap days are are present in years divisible by 4, unless the year is divisible by 100. However if the year is divisible by 400 it still is a leap year. So, 2000 is a leap year, 1900 and 1800 were not.