Lummus Park is South Beach's default event site, and several times a year large parts of it are fenced.
January has traditionally brought Art Deco Weekend, the Miami Design Preservation League's street festival, which closes Ocean Drive and spills into the park with stalls, classic cars and lectures. It is free, it is the single best weekend of the year to be here if the architecture is why you came, and it makes the beach crossing slower.
February has traditionally brought the big wine and food festival, whose marquees occupy a substantial run of the sand between roughly 11th and 14th Streets for the better part of a week, including build and strike days. If you booked an ocean-facing room for that week, expect a view of a tent.
Early December is Art Basel Miami Beach. The fair itself is at the convention centre several blocks north-west, but the island-wide effect is total: hotel rates, restaurant availability, rideshare surge and pop-up activations, some of them on this sand.
March is spring break, and the park is where the city's management of it is most visible — staffed beach entrance checkpoints at selected cross streets, bans on coolers, glass, tents, inflatables and unpermitted amplified music, and a conspicuous police presence.
4 July brings fireworks off the beach and a crowd to match.
Dates move. Check the City of Miami Beach events calendar before you build a day around this strip.