For me, worst is February, although we had some Valentine's Day promotions and "extra" traffic hitting this year so, in the end, Feb will be a "normal" month, which is actualy a "good" month, if you know what I mean.
Best? Hmmm... I can give you time spans, not specific months: April-June are good, as are Oct-Dec. So the other months of the year fall into the "normal" (meaning: steady sales/average) category.
PS: What will76 said.
