In an article featured on the first page of the Polish "Kurier", the advertisement for the Pułaski Parade on Oct. 6, read "Spotykamy się 6. października 2013 na 5tej alej..". I was wondering if the reason for the text reading in the imperfective is that it's an annual event which takes place regularly, therefore, it's a constant as opposed a once-in-a great-while occurence.
Is this correct?
No - it's simply the present tense. Polish, like English, can use the present tense to express future plans. In English, it would probably be more natural to say, "We are meeting on the 6th October", than "We will meet on the 6th October". Similarly in Polish.