Blue Spring in September: Water Temperature, Rain Days and Parking

BLUE SPRING · SEPTEMBER · 28.9° N

The spring does not keep a calendar. A USGS gauge on the run, station 02235500, read 74.3°F (23.5°C) on September 11, 2026, and it reads close to that every day of the year. The air above it is another matter: NOAA’s 1991-2020 normals put September at an average high of 89.5°F, an average low of 73.9°F, and 6.55 inches of rain.

That distance between air and water is what September sells. You get the hottest afternoons of any swimming month at Blue Spring over a run that never warms, 3,050 feet of boardwalk to walk it off, and a 187-space parking lot that settles the whole day: when it fills, the gate closes until cars leave.

On this page

• September highs, lows and rain days89.5°F days, 9.8 wet days
• How cold the spring water feels74.3°F at the vent, year-round
• Parking, cabins and booking aheadThe 187-space lot and six cabins
• Things to do at the park in SeptemberBoardwalk, platforms, launch, swim area
• A two-day plan around the heatThe September itinerary, hour by hour
• August or October insteadHow the three months compare
• Is September the right month?Our September verdict

The park’s year-round shape lives on our Blue Spring guide, and the winter animals belong to swimming with manatees. Two admissions before the numbers start: we could not verify the entrance fee, the opening hours or a manatee count, because Florida State Parks’ site refuses automated reads. We quote none of the three.

Blue Spring weather in September: average highs, lows and rain days

Every air figure here comes from one thermometer, and it is not at the spring. NOAA’s monthly normals for 1991-2020, station USW00012841 at Orlando Executive Airport, about 27 miles (44 km) south, give September 89.5°F by afternoon, 73.9°F before dawn and 6.55 inches of rain. Those are measured station normals, not a reanalysis grid cell averaged over a square of Central Florida. They describe the air over Volusia County. The water has its own gauge and its own answer.

Measurable rain falls on 9.8 days in an average September, so a little under one day in three ends up wet, and 1.8 of them deliver an inch or more. It lands in the afternoon: heat builds through lunch, a cell sits over the St. Johns valley for an hour, then the boardwalk drips for a while after. A three-day visit that does its swimming before noon usually gets all three swims in.

Day and night barely separate, 15.6°F between the average high and the average low, and that low is still 73.9°F. Nothing warm needs to go in the bag. What does: a rain shell you can ball up, a dry bag for phones on the inch-or-more days, water shoes for the steps into the run, and a second towel, because the first one will not dry in September humidity.

On September 15 the sun rises at 7:09 a.m. and sets at 7:31 p.m. local time, for 12 hours 22 minutes of daylight. Under cypress and live oak, usable light on the boardwalk goes earlier than the clock suggests. Start the last walk by 6:30 p.m. and you will not be finishing it by phone flashlight.

How warm is the water at Blue Spring in September?

Two temperatures matter this month and they sit far apart. The air runs 89.5°F by afternoon and 73.9°F before dawn, a spread of 15.6°F. The spring runs 74.3°F, which is what the USGS gauge at station 02235500 read on September 11, 2026, a single instantaneous reading rather than a monthly mean. The same gauge reads close to that in January. Your first step into the run in September is a drop of about 15 degrees from the air above it.

What you wear is what you swim in. A rash guard and shorts carry the whole day: the 89.5°F afternoon dries you in minutes and the 74.3°F water pulls the heat straight back out. The same gauge measured 168 cubic feet per second leaving the vent. That volume is why the run stays clear enough to count the sand ridges under you, since the water is replaced faster than it can cloud.

Freezing nights are not a September question at this latitude, with the month’s average low at 73.9°F. Our NOAA normals carry no freeze-day count for the month, so we give no number. The chill comes from below instead, on an overcast morning when the air has not climbed yet and the run still holds 74.3°F. Swimmers who cool fast tend to alternate: twenty minutes in the water, ten on the warm boards.

How busy is Blue Spring in September? Parking, cabins and what you can book

The thing that runs out at Blue Spring is parking. The state’s 2024 facilities inventory counts 187 spaces, one designated swimming area and six cabins for the entire park. We found no occupancy series and no monthly room-rate data for the area, so we crown no month cheap and none expensive. A 187-space lot fills on a warm weekend, and once it does the gate closes until cars leave.

Arrival time is therefore the main lever a September visitor has, and it is a morning lever. The six cabins are the whole stock of beds inside the gate; we could not verify how far ahead they open for reservation, so call the park before you build a weekend around one. Everyone else stays outside the boundary and drives in early, which beats testing the lot at noon.

On lodging tax we have nothing verified. We could not read a current county rate from a primary source, so we give no percentage. Assume the room rate you see quoted is not the number you pay, and read the tax line on the booking screen before confirming. Our Florida trip cost guide covers how those add-ons stack across a week.

Paying more changes exactly one thing in September: where you sleep relative to that gate. A cabin inside the park buys the swim before the first wave of traffic and a shaded walk back when the afternoon reaches 89.5°F. Rented gear at the launch may do something similar for the river, though we could not verify its rates. What the money cannot buy is the water, which arrives at 74.3°F for everybody.

Things to do at Blue Spring in September

September still belongs to swimmers. Blue Spring’s cold-weather identity is the manatee season, when the animals move into the run and the park’s water rules change, and we could not verify either the dates those rules take effect or how many animals arrive. In September the run is a swimming hole at 74.3°F. The winter side of this park sits in our manatee guide.

The state’s inventory is specific about what the park holds: 3,050 feet of boardwalk following the spring run, three observation platforms along it, one launch for canoes, kayaks and tubes, and one designated swimming area. Those 3,050 feet are the park’s spine, carrying you from the vent down toward the St. Johns, and the platforms are where you stand when the swimmers are in the water below.

None of that moves with the month. The air over it does. September averages 89.5°F in the afternoon and October 84.4°F, so the same 74.3°F water reads as relief now and as a decision in four weeks: 15.2°F below the air in September, 10.1°F below it in October. The gauge reading stays the same in both cases.

On money inside the gate, our reading came up short. Florida State Parks’ site returns an error to automated requests, so we could not verify the entrance fee or the opening hours and we quote neither. What we can say is that the boardwalk, the three platforms and the swimming area carry no separate charge once you are through the entrance.

Blue Spring in September: a two-day itinerary

Day one starts at the gate before the 187 spaces are spoken for, which on a September weekend means early. Swim first, while the air is climbing from its 73.9°F overnight low and the 74.3°F water still reads cool. Walk the 3,050 feet of boardwalk mid-morning and stop at all three platforms. Sit out the middle of the day in shade, then come back for the last light: sunset is 7:31 p.m. on September 15.

Day two goes on the water. The single launch takes canoes, kayaks and tubes toward the St. Johns, and the morning is the flat half of a September day. If the sky builds, and 1.8 days in an average September drop an inch or more, cut the paddle short and move the swim forward, since the spring holds 74.3°F in the rain too. For a washed-out afternoon, our Florida things-to-do guide has the indoor fallbacks.

Blue Spring in September vs August and October

Line the three up and the trend runs one way. August averages 91.8°F by day, 75.3°F at night, 7.66 inches of rain across 11.7 wet days. September eases to 89.5°F and 73.9°F, with 6.55 inches over 9.8 wet days. October is where the break happens: 84.4°F, 68.3°F, 3.24 inches and 4.7 wet days. All three figures for the spring itself are the same figure, 74.3°F.

Push the trip four weeks later and you gain 5.1°F off the afternoon, 3.31 inches of rain and 5.1 wet days. You give up the easiest swimming: in October the air stands only 10.1°F above the water, and the park’s cold-season rules approach on dates we could not verify. Four weeks earlier, August charges 1.11 inches more rain and 1.9 more wet days for 2.3°F of extra heat. Our August page runs those numbers.

Is September a good time to visit Blue Spring?

Yes, if you came to swim. With the air at 89.5°F, water at 74.3°F is the best thing available in Central Florida that afternoon, and the park rewards anyone willing to set an alarm for the lot. No, if your plan needs dry ground: 9.8 wet days puts rain on roughly one afternoon in three, and 6.55 inches is serious water falling out of the sky, not a passing sprinkle.

Readers in that second camp should take October. Its 3.24 inches across 4.7 wet days come to less than half of September’s rainfall, the average high falls to 84.4°F, and the boardwalk becomes a noon activity rather than a dawn one. The trade is the water: 74.3°F under an 84.4°F sky asks more of a swimmer than it does under 89.5°F. Our Florida timing guide puts that in statewide context.

What September holds that its neighbors do not is August’s swimming conditions minus 1.11 inches of rain and 1.9 wet days, with 12 hours 22 minutes of daylight on the 15th to spend in them.

The last word

The September decision is what time you leave the house. Those 187 spaces are the only thing at Blue Spring that can turn you away, and they go in the morning. Florida law, for its part, files this spring in a protected class: Statute 373.802(5) defines Outstanding Florida Springs as every historic first-magnitude spring the Florida Geological Survey recognizes, plus six more named by hand in the text. That is the company the vent’s 168 cubic feet per second keeps, and in September you get to swim in it at 74.3°F while the air sits at 89.5°F.

Sources & data for this guide

• September air normals (89.5°F high, 73.9°F low, 6.55 in, 9.8 days at 0.10 in, 1.8 days at 1 in) · NOAA NCEI monthly normals 1991-2020, station USW00012841, Orlando Executive AP, about 27 miles from the spring · checked Sep 24, 2026
• August and October normals used in the comparison · same NOAA NCEI 1991-2020 series and station · checked Sep 24, 2026
• Daylight of 12 h 22 min and sun times for September 15 · sunrise-sunset.org, converted to local time · checked Sep 24, 2026
• Spring water at 74.3°F (23.5°C) and 168 cubic feet per second · U.S. Geological Survey, National Water Information System, station 02235500 Blue Spring, instantaneous reading · checked Sep 24, 2026
• 187 parking spaces, 3,050 feet of boardwalk, six cabins, three observation platforms, one launch, one designated swimming area · Florida Department of Environmental Protection, Recreational Facilities Inventory, 2024 annual report · checked Sep 24, 2026
• Outstanding Florida Springs definition · Florida Statutes 373.802(5) · checked Sep 24, 2026
• We could not verify the entrance fee, the opening hours, a manatee count or a county lodging-tax rate: floridastateparks.org returns an error to automated reads and the FWC manatee page renders client-side · checked Sep 24, 2026

To plan your stay

• Best Time to Visit Blue Spring: Weather by Month, Manatee Season and the Quiet Weeks
• Blue Spring in August: Weather, Water Temperature and Parking
• Blue Spring in October: Water Temperature, Rain Days and Parking Limits
• Blue Spring in July: Weather, Crowds, Parking and the 74.3°F Water

Nearby places

• De Leon Springs: Swimming, Table-Griddle Pancakes and 240 Parking Spaces
• Wekiwa Springs: Water Temperature, Swimming Area and the 325-Space Lot
• Silver Glen Springs, Florida: Swimming, Clear Water and Weekend Crowds