September is a tough month at Biscayne — it ranks 9th of the twelve here. Expect about 26% fewer visitors than May, the park's peak — 45,559 visits on average. Days run around 89°F by afternoon and 73°F at night, with 12.3 hours of daylight.
September against the park's best
| Month | Verdict | Avg. visits | vs. peak | High | Low | Snow | Daylight |
|---|---|---|---|---|---|---|---|
| September (this page) | Tough | 45,559 | −26% | 89°F | 73°F | 0" | 12.3 h |
| January (best) | Good | 45,467 | −26% | 76°F | 55°F | 0" | 10.7 h |
| May (peak crowds) | Tough | 61,658 | peak | 86°F | 68°F | 0" | 13.4 h |
Weather figures are for the Convoy Point area — the Perrine 4W station. Visits are 2021–2025 averages; climate normals cover 1991–2020. Conditions vary across the park; check current status before you go.
Common questions
Is September a good time to visit Biscayne?
It is the tough season — doable with preparation, but the numbers say most people should pick another month. September ranks 9 of 12 at Biscayne on crowds, weather, daylight, and access together.
How crowded is Biscayne in September?
About 45,559 recreation visits on average — 26% below May, the park's peak.
How warm is Biscayne in September?
Average highs around 89°F and lows around 73°F at the Perrine 4W station.
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