Madison Blue Spring in September: Weather, Water Temperature and How It Compares to August

FLORIDA · MADISON BLUE SPRING · SEPTEMBER

Madison Blue Spring read 73.2°F on the USGS gauge in September. It reads close to that in February, and it will read close to that next July. September changes everything above the waterline instead: an average high of 87.8°F, an average low of 66.5°F, 4.22 inches of rain spread over a handful of afternoons, and a sun that goes down at 7:39 p.m. on the 15th.

Set beside its neighbors, this is the month that lets go. August runs 91.5°F highs and 8.0 wet days. September takes both down, to 87.8°F and 5.2. October drops the air to 80.5°F and the nights to 56.8°F, turning a warm-air trip into a cool-morning one. If you are still choosing the week rather than the place, our Florida calendar does that job.

On this page

• Madison Blue Spring weather in September87.8°F highs, 4.22 inches, 5.2 wet days
• Water temperature at the spring73.2°F on the USGS gauge
• Fees, gate hours and lodging taxWhat we could and could not verify
• Things to do at the spring in September72 cubic feet per second, and no launch ramp
• A two-day plan around the heatWater before noon, shade after
• September, August or October?How the three months compare, degree by degree
• Is September a good time to go?Yes with flexible dates, no with a fixed booking

Two different instruments run through the sections below, and they do not measure the same thing. The air comes from a NOAA weather station in Georgia. The water comes from a USGS gauge in the spring run itself. Keeping them apart is the whole trick of planning a Florida spring trip in a hot month.

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

The air normals come from NOAA’s National Centers for Environmental Information, 1991-2020 period, station USW00093845 at Valdosta Regional Airport in Georgia, about 27 miles from the spring. September there averages a high of 87.8°F, a low of 66.5°F and 4.22 inches of rain. Every air figure here is that station’s real thermometer rather than a grid-cell reanalysis, and the trees over a spring run will always shave a few degrees off an airport tarmac.

Measurable rain falls on 5.2 days in an average September, roughly one day in six, and 1.0 of those days delivers an inch or more. In practice that is not a washed-out week. It is a soaking afternoon or two dropped into an otherwise usable month, and north Florida’s wet-season storms tend to build after lunch rather than at breakfast. Water time in the morning is the cheapest insurance going.

The spread between 87.8°F and 66.5°F is 21.3 degrees, and you feel all of it if you arrive early. Pack for two climates in one day: a fleece or a hoodie for a 7 a.m. start on wet skin, then nothing but shade and water by two o’clock. Add a second towel. At this humidity the first one does not dry between sessions.

On September 15 the sun rises at 7:16 a.m. and sets at 7:39 p.m. local time, giving 12 hours 23 minutes of daylight. That is already about 45 minutes shorter than midsummer, and under tree cover the useful light goes before the official sunset does. Anyone planning a late second swim should treat 6:30 p.m. as the practical cutoff for getting gear back to the car dry.

How warm is Madison Blue Spring in September?

The USGS gauge at the spring, station 02319302, read 73.2°F (22.9°C) on September 11, 2026. Cool enough to catch your breath on entry, never cold enough to keep you out. One caveat on that number: water temperatures published as monthly averages are usually built from daily maxima, a shade warmer than a true 24-hour mean. Ours is neither. It is a single instantaneous reading, and the gauge sits close to that figure every day of the year.

Against the air, that reading behaves very differently at either end of the day. At the 66.5°F average low, water at 73.2°F is the warm place to be, and getting out at 7:30 a.m. is the unpleasant part. By mid-afternoon, with the air at 87.8°F, the same water is a 14.6-degree drop and the reason people drive here in the first place. Morning swimmers want the hoodie; afternoon swimmers want the shade.

Freezing nights are not a September problem in this part of Florida: the month’s average low is 66.5°F, and our normals show nothing near 32°F. Those nights belong to a later page in the series. October already brings the average low down to 56.8°F, which is the first month where a cold exit from the water becomes a real consideration.

How busy is Madison Blue Spring in September? Crowds, prices and the demand peak

September lands in Florida’s shoulder, after the school year has restarted across north Florida and south Georgia and before the dry season refills the state. We found no occupancy series and no room-rate series for Madison County, so we crown no month cheapest and none dearest. The calendar fact behind the discounts is different from a price claim: the Atlantic hurricane season runs June 1 to November 30 and peaks around September 10, a date our Florida orientation sets out in full.

That peak sets the booking rule for the month. Reserve rooms and rental cars on refundable terms for any September trip within driving distance of the spring, and keep the dates loose rather than the deposit large. On the park itself we have less to offer than we would like: we could not verify an entrance fee or a gate hour, because floridastateparks.org answers automated readers with a 403 error. Call the park the week you drive.

We could not verify a lodging-tax rate for Madison County either, so we give no percentage. Budget for a bed tax on top of the quoted room rate and let the confirmation email tell you the number.

The one purchase that changes a September day here is thermal protection. Ten minutes in 73.2°F water is a relief when the air is at 87.8°F; two hours of it is a different proposition, and a rented shorty or a 3 mm suit converts a short dip into a full morning. Come back in October, with the air at 80.5°F, and that same suit stops being optional. Our trip-cost guide handles the rest of the budget.

Things to do in Madison Blue Spring in September

September does one thing August cannot: it keeps the heat that makes cold water worth driving for while cutting the storm count. August logs 8.0 days with 0.10 inch or more and 5.11 inches of rain. September logs 5.2 days and 4.22 inches, with the afternoon high still at 87.8°F. Fewer interrupted afternoons, nearly the same reward for getting in.

The spring itself is the attraction and the numbers are worth knowing before you go. The USGS gauge measured 72 cubic feet per second leaving the vent, which is why the water stays clear: it is replaced faster than it can cloud. Florida’s statute 373.802(5) defines Outstanding Florida Springs as every historic first-magnitude spring the Florida Geological Survey identifies, plus six named by hand in the law. Read the statute as state context, not as a label for Madison Blue.

What the month does not change is the water, and what it changes is the gap. August puts 18.3 degrees between the average high and that 73.2°F reading. September puts 14.6. October puts 7.3, and by then the swim has become a plunge you talk yourself into. Plan the day around the air, because the spring will be exactly where you left it in any month.

One practical limit, from the Florida Department of Environmental Protection’s 2024 recreational facilities inventory: the park has no designated swimming area listed, and no canoe, kayak or tube launch either. That is an inventory of designated facilities rather than a prohibition notice, but it means nobody should arrive expecting a lifeguard, a roped-off shallow end or a float trip downstream. Families wanting those should look at the options in our Florida with kids guide.

Madison Blue Spring in September: a two-day itinerary

Day one starts at the water by 8 a.m., not long after the 7:16 sunrise, with the night’s 66.5°F still hanging in the trees. Give the water the whole morning while the sky is clean, then be out by one o’clock and spend the hottest stretch under cover, since wet-season storms here build in the afternoon. Come back around five for a second session, when the air is falling off its 87.8°F peak, and have the gear in the car before the 7:39 p.m. sunset.

Day two repeats the shape with a shorter morning and a real breakfast, unless the sky turns. Rain does nothing to a 73.2°F spring, but lightning ends the day regardless, and 1.0 September day in an average year drops an inch or more. That becomes a driving day: the springs belt, St. Augustine’s old town or a run toward the Gulf, all laid out in our Florida road trip routes.

Madison Blue Spring in September vs August and October

Across the three months the air moves 11 degrees at the high end and 14.2 at the low end, while the spring moves essentially not at all. Rain follows the same slope: 5.11 inches and 8.0 wet days in August, 4.22 and 5.2 in September, 3.71 and 4.1 in October. All of these air figures come from the same NOAA station and the same 1991-2020 period, so the comparison is like for like.

Shift four weeks earlier and you buy 3.7 degrees of extra afternoon heat, which makes the water feel better, at the cost of nearly three more wet days. Shift four weeks later and you gain the driest month of the three and lose the point of the trip: a 7.3-degree gap between air and water is not a plunge, and the 56.8°F nights make an early start genuinely cold on wet skin.

Is September a good time to visit Madison Blue Spring?

Yes, if your dates can move and your gear is your own. Swimmers, snorkelers and divers who want hot air over cool water get the best version of that trade this month, with fewer storm afternoons than August and the same 73.2°F reading. No, if you need a fixed non-refundable week in the statistical peak of hurricane season, or if you are bringing small children expecting a marked swim area and a tube launch that the state’s inventory does not list.

If that is a no, October is the month to shift to rather than November: 3.71 inches of rain over 4.1 wet days is the driest stretch of the three, the storm odds fall with the season, and the drive is more pleasant at 80.5°F. Pack for the 56.8°F nights and accept that the water will feel colder, not because it changed but because you did.

No other month combines a 14.6-degree drop from air into water with only 5.2 rain days: August has the bigger drop and the wetter sky, October has the dry sky and almost no drop at all.

The last word

Make the call on the gauge rather than the forecast. USGS station 02319302 publishes Madison Blue’s temperature and its discharge, so the morning you load the car you can see for yourself whether the vent is still pushing its 72 cubic feet per second and the water is still sitting near 73.2°F. Then look at the sky, since that is the only variable September actually controls. Book the room refundable, drive up for a two-day weekend, and give the water the hours before noon.

Sources & data for this guide

• September air normals (87.8°F / 66.5°F / 4.22 in) and rain-day counts · NOAA NCEI monthly normals 1991-2020, station USW00093845, Valdosta Regional AP, GA · checked Sep 24, 2026
• August and October normals used in the comparison table · same NOAA station and period · checked Sep 24, 2026
• Daylight, sunrise and sunset for September 15 · sunrise-sunset.org, converted to local time · checked Sep 24, 2026
• Water temperature 73.2°F and discharge 72 cubic feet per second · USGS National Water Information System, station 02319302 Madison Blue Spring, instantaneous reading · checked Sep 24, 2026
• No designated swimming area, no canoe, kayak or tube launch listed · Florida DEP Recreational Facilities Inventory, 2024 annual report · checked Sep 24, 2026
• Outstanding Florida Springs definition · Florida Statutes 373.802(5), leg.state.fl.us · checked Sep 24, 2026
• Editorial admission: we could not read an entrance fee, a gate hour or a Madison County lodging-tax rate. floridastateparks.org returns a 403 error to automated reads · checked Sep 24, 2026
• The weather station sits about 27 miles from the spring and measures the air, not the water · call the park before you drive, since hours and fees change.

To plan your stay

• Madison Blue Spring: When to Go, Month by Month Highs, Rain and Daylight
• Madison Blue Spring in August: 91°F Air, 73°F Water and 8 Rain Days
• Madison Blue Spring in October: Water Temperature, Air Normals and Rain Days
• Madison Blue Spring in July: Water Temperature, Heat and Rain Days

Nearby places

• Wes Skiles Peacock Springs: No Swimming Area, 68 Parking Spaces, Cave Diving
• Troy Spring: 71°F Water, the Madison Wreck and 25 Parking Spaces
• Ichetucknee Springs: Tubing, Swimming Areas and 909 Parking Spaces