Biscayne National Park in September
September at Biscayne National Park averages a daytime high near 90°F and an overnight low around 79°F, with about 7.5" of precipitation. Visitation runs about 0.8× the park's average month, which makes September a quiet month here.
- Average low
- 79°F
- Average high
- 90°F
Range across the year: 63°F to 91°F
- Precipitation
- 7.5 in
- Daylight
- 12.1 hours
Roughly 7% of the park's yearly visitors come in September: about 39,000 recreation visits in a typical year, based on National Park Service monthly counts from 1979 to 2025.
That makes September the 10th-busiest of the park's twelve months, sitting between the July peak (1.2×) and the October low (0.7×).
On our Best Time to Visit score September rates 40/100 ("Poor"). Our recommended month is November: pleasant weather with noticeably thinner crowds (shoulder season).
The daily average of about 85°F is hot, with afternoons near 90°F to plan the day around. These figures are 1991–2020 NOAA climate normals from the nearest station, about 13 miles from the park.
Because June, July and August together draw about 27% of annual visitors, choosing September instead steps outside that summer crush — the single biggest lever on how crowded the park feels.
You'll have about 12.1 hours of daylight in September to explore — between the 10.4-hour midwinter low and the 13.6-hour summer high.
Park-wide, 2025 drew 486,567 recreation visits, down 5% from 512,213 in 2024.
Across the past decade overall visitation has risen about 17.1%, so a September visit is likely to feel busier than it did a few years ago.
How September compares with the months around it
| Month | Avg high / low | Crowds | Best-time score |
|---|---|---|---|
| August | 91°F / 79°F | 1.0× Average | 30 Poor |
| September | 90°F / 79°F | 0.8× Quiet | 40 Poor |
| October | 87°F / 76°F | 0.7× Quiet | 62 Good |
All twelve months at Biscayne, with the best time to visit.
Frequently Asked Questions
September averages a daytime high near 90°F and an overnight low around 79°F at Biscayne National Park, with about 7.5 inches of precipitation. These are 1991–2020 NOAA climate normals from the nearest station, about 13 miles from the park, so conditions inside the park can differ, especially at other elevations.
September is quiet at Biscayne National Park (about 0.8× the average month). Our best-time score rates it "Poor" at 40/100. Our recommended month is November.
The busiest month is July and the quietest is October. September sits at about 0.8× the park's average, or 7% of annual visitation.
A typical September sees about 39,000 recreation visits at Biscayne National Park, based on National Park Service monthly counts from 1979–2025.
Where to stay near Biscayne in September
Booking a September trip to Biscayne National Park? Compare hotels, cabins and vacation rentals near the park with live September availability and prices.
Top-rated places to stay near Biscayne
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
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See the full ranking of the best national parks to visit in September.
Source: National Park Service Visitor Use Statistics (1979–2025), NOAA NCEI Climate Normals 1991–2020. Updated 2026-10-11.