Clearwater in September: Heat, Rain Days and 86.8°F Water

CLEARWATER · SEPTEMBER · 27.98° N

September is the month the Gulf off Clearwater stops being refreshing and starts being warm: 86.8°F in the marine record, against afternoons that normally reach 88.9°F. Rain arrives in loud, short installments, 6.40 inches of it spread across the month, and the beach day survives most of them.

It is also the month with an asterisk. The Atlantic hurricane season runs June 1 to November 30 and peaks statistically around September 10 (NOAA National Hurricane Center, as set out in our Florida orientation). Book a refundable rate and September works well. Book a nonrefundable one and you are placing a bet on the tropics.

On this page

• Clearwater weather in September88.9°F highs, 6.40 inches, 8.6 wet days
• Can you swim in September?The Gulf at 86.8°F
• Crowds, prices and the lodging tax12% on the nightly rate, before resort fees
• Things to do in SeptemberHoneymoon Island, Caladesi, Anclote Key
• A two-day plan, including a wet afternoonTwo days timed to a 7:15 a.m. sunrise
• September vs August and OctoberHow the three months compare, line by line
• Is September a good time to visit?Who should come, and who should wait for October
• The month either sideOctober, at 84.2°F and 2.49 inches

Three months are genuinely on the table for a Gulf beach week: August at 90.6°F and 8.83 inches, September, and October at 84.2°F and 2.49 inches. The wider state calendar, region by region, sits in the best-time guide.

Clearwater weather in September: average highs, lows and rain days

Every figure here comes from one thermometer rather than a grid cell: NOAA station USW00012873, listed as ST PETERSBURG INTL AP, whose 1991-2020 normals give September an average high of 88.9°F, an average low of 75.2°F and 6.40 inches of rain. The gauge sits at PIE, between St. Petersburg and Clearwater, on the bay side rather than the Gulf. Clearwater Beach gets a sea breeze the airport never feels, so the difference falls on the afternoon maximum and barely touches the overnight low.

8.6 September days record at least 0.10 inch, which puts measurable rain on roughly one day in three and a half, and 2.0 days deliver a full inch or more. That is Florida’s wet season behaving as it does statewide, in near-daily afternoon storms (our state guide lays out the two-season pattern). A storm that drops an inch usually costs you forty-five minutes under a roof, and the sand dries before the light goes.

The two normals sit 13.7°F apart, and the low is a dawn reading rather than a dinner one. Nothing in the bag needs to be warm. A rain shell that breathes, quick-dry clothes, and shoes you are willing to soak cover the month. The same shoes handle 3.4 miles of trail at Honeymoon Island, where the shade runs out faster than the water does.

On September 15 the sun rises at 7:15 a.m. and sets at 7:36 p.m. local time, giving 12 hours 21 minutes of daylight. Dinner happens after sunset without anyone planning it, and a six o’clock swim is still a swim in full sun. The early hour is the one worth setting an alarm for: it is the only stretch of the day when 88.9°F is not the operating condition.

Can you swim in Clearwater in September? Sea temperature and what the water feels like

The Gulf off Clearwater averages 86.8°F in September in the Open-Meteo Marine API, over the ten years 2015-2024. Read that number for exactly what it is: a mean of daily maxima, so a shade warmer than a 24-hour average, and warmer than what meets you at half past seven in the morning. It is not a station reading like the air normals above, and the two should not be treated as the same class of measurement.

At 86.8°F there is no entry shock and no acclimation minute. The water runs above the month’s average overnight air low of 75.2°F, so at dawn the Gulf is the warm part of the morning. The flip side arrives in the afternoon: water that warm does not cool you down, and a long swim under an 88.9°F sky is not the heat break it would be in March.

We could not read a wind or swell series for Clearwater, so no sea state is described here that we did not measure. What the calendar does carry is the season itself, June 1 to November 30, with its statistical peak around September 10 (NOAA National Hurricane Center, cited in our Florida orientation). A refundable rate and a look at the tropics in the week before you fly are the whole precaution.

How busy is Clearwater in September? Crowds, prices and what the lodging tax adds

September falls between two calendars: school is back across the country, and Florida’s dry-season run of winter visitors does not begin until November (the state calendar sets the dates). Clearwater’s own airport helps size the month. PIE boarded 1,228,048 passengers in calendar year 2024, which the FAA classes a small hub.

We could not read an occupancy or room-rate series for Pinellas County, so no ranking of the year’s rates appears here and no lead time in weeks either. What can be said with the data in hand is narrower and more useful: the cancelation policy matters more in September than in February, because September sits inside the hurricane season and February does not. Choose the booking you can undo, then stop optimizing.

On the bill itself, one figure is fixed. Pinellas County levies a 6.0% transient rental tax on every night booked, collected alongside the 6% state sales tax (Florida Department of Revenue, form DR-15TDT, revision 03/25). That is 12% on the nightly rate you were quoted, before any resort fee. The resort fee is set by the property and is not a tax, so it sits outside that calculation and inside your total. The wider budget picture is in our Florida cost guide.

If one line of the budget deserves the upgrade in September, it is the refundable rate rather than the ocean view. The 12% rides on the higher number too, so compare the two options on the total and not on the headline. Everything else the month asks for costs nothing: an earlier alarm, and a roof to sit under for forty-five minutes.

Things to do in Clearwater in September: Honeymoon Island, Caladesi and Anclote Key

Through September the Gulf still reads 86.8°F in the marine series. By October the same series gives 79.0°F, 7.8°F cooler in four weeks, and swimming turns into a decision instead of the default. Anything built around long hours in the water, snorkeling the flats, a float that lasts an afternoon, gets its last easy month here.

Three state parks hold the beaches, and Florida counted them in its 2024 inventory. Honeymoon Island: 2,021 parking spaces, 4 miles of beach, one designated swimming area, 3.4 miles of hiking trail, 1,671 feet of boardwalk. Caladesi Island: 3 miles of beach, 2.5 miles of trail, one canoe, kayak and tube launch, and not a single parking space, because you reach it by ferry or your own boat. Anclote Key Preserve: 6.7 miles of beach and 1,408 feet of boardwalk.

At those three, September moves the air rather than the water. An 88.9°F normal makes 3.4 miles of Honeymoon Island trail a before-ten proposition, while the same walk in October sits under an 84.2°F high. Parking is the month’s other variable: 2,021 spaces absorb a Saturday, and Caladesi, with no lot at all, is capped by ferry seats whatever the thermometer says.

On what any of this costs at the gate, plainly: we could not read a single park fee or opening hour for Clearwater, because the operators’ pages either refuse machine reads or render only in a browser. No entrance price is quoted here, and nothing is called free that we did not verify. Check the gate price when you book, and price the rest of the day with our Florida things-to-do guide.

Clearwater in September: a two-day itinerary

Day one runs on the sun. It clears the horizon at 7:15 a.m. on the 15th, and that first hour is the only comfortable one for the 3.4 miles of trail at Honeymoon Island. Swim the designated area from ten, with the Gulf near 86.8°F. Get under a roof from about one, when the 2.0 inch-days of the month tend to announce themselves. Back on the sand by five, sunset at 7:36 p.m., dinner after it.

Day two belongs to Caladesi, which has no parking and therefore runs on ferry seats: take the earliest crossing you can get, walk some of the 3 miles of beach away from the landing, and save the 2.5 miles of trail for a cooler morning. If the sky closes in, the normals are the guide: 8.6 days record 0.10 inch and only 2.0 reach a full inch, so waiting out a cell beats rebuilding the day. If the forecast looks committed rather than passing, move the island to the next clear morning.

Clearwater in September vs August and October

Laid side by side, the three columns sort themselves. August runs 1.7°F hotter by day and drops 8.83 inches across 12.5 wet days. September takes 6.40 inches over 8.6 days with the water at 86.8°F. October cuts the rain to 2.49 inches over 3.4 days, pulls the average high to 84.2°F, and drops the overnight low from 75.2°F to 69.7°F, which is the first real night air of the Clearwater year.

Shift four weeks later and you gain 5.2 fewer wet days and 3.91 fewer inches of rain, at the cost of 7.8°F of sea temperature and 4.7°F of afternoon air. Shift four weeks earlier into August and the water is warmer still at 89.3°F, paid for with 3.9 extra wet days and 2.43 more inches. Nobody gets both the bathwater and the dry afternoons.

Is September a good time to visit Clearwater?

Straight answer: yes if the trip is built around the water, and no if your dates cannot move and your booking cannot be canceled. A 86.8°F sea, 88.9°F afternoons and 8.6 wet days describe a genuine beach month with weather inside it. Families who need the pool, the swim and the early trail all in one week get more out of September than out of any dry-season month at 84.2°F or below.

If the storm risk is the sticking point, October is the answer, and the numbers say why: 2.49 inches over 3.4 wet days, an 84.2°F average high, a sea still reading 79.0°F. That trade buys dry afternoons and costs you the long swim. The October page runs the month in full.

Among the three, only September pairs 86.8°F water with a rain total 2.43 inches under August’s, and it does it with daylight holding past 7:30 in the evening.

The last word

Book the rate you can cancel, keep the walking for the hour after 7:15 a.m., and let the ferry set the shape of day two. One figure worth carrying: Honeymoon Island’s 2,021 spaces are the largest parking count of any state park in Florida’s 2024 inventory, and Caladesi, three miles of sand across the channel, has none at all. That geography decides a Clearwater Saturday in any month, and September is the one where the water still reads 86.8°F.

Sources & data for this guide

• September normals (88.9°F / 75.2°F / 6.40 in) · NOAA NCEI monthly normals 1991-2020, station USW00012873, ST PETERSBURG INTL AP · checked Sep 12, 2026
• Rain-day counts (8.6 days at 0.10 in, 2.0 days at 1.00 in) · same NOAA station and period · checked Sep 12, 2026
• August and October normals used in the comparison table · same NOAA station and period, not estimates · checked Sep 12, 2026
• Sea surface 86.8°F (and 89.3°F / 79.0°F) · Open-Meteo Marine API, mean of daily maxima 2015-2024 · checked Sep 12, 2026
• Sunrise 7:15 a.m., sunset 7:36 p.m. and 12 h 21 min of daylight on September 15 · sunrise-sunset.org, converted to local time · checked Sep 12, 2026
• Park counts at Honeymoon Island, Caladesi Island and Anclote Key · Florida Department of Environmental Protection, Recreational Facilities Inventory, 2024 annual report · checked Sep 12, 2026
• Lodging tax 6.0% county plus 6% state · Florida Department of Revenue, form DR-15TDT, revision 03/25 · checked Sep 12, 2026
• PIE boardings, 1,228,048 in CY2024 · Federal Aviation Administration passenger boardings · checked Sep 12, 2026
• Hurricane season dates and the September 10 statistical peak · NOAA National Hurricane Center, as cited in our Florida orientation guide · checked Sep 12, 2026
• Editorial admission: no bus or ferry fare, no park entrance fee and no opening hour could be read for Clearwater. gohart.org returned 404, psta.net did not respond, tampaairport.com returned 403 · checked Sep 12, 2026. No amount was invented to fill the gap.