Nothing about Mardi Gras is predictable – not even the date. Unlike Christmas or the 4th of July which always fall on the same calendar day, the only thing you can count on for sure with Carnival is that Fat Tuesday will fall on, well, a Tuesday. That’s because the date of Easter is tied to the moon (it’s always the first Sunday after the full moon that follows the spring equinox) and Mardi Gras is tied to Easter.
Because Easter can fall on any Sunday between March 23 and April 25, and Mardi Gras is always 47 days before Easter, Zulu and Rex can roll on any Tuesday between Feb. 3 through March 9.
New Orleans weather on Mardi Gras Day can be unpredictable as well. It can be shorts weather in early February and you might very well need a coat in March.