Isla Mujeres in September: Weather, Rain Days, Sea Temperature and Hurricane Season

MEXICO · ISLA MUJERES · SEPTEMBER

September on Isla Mujeres is a swimmer’s month with a weather asterisk. The sea off the island averages 87.1°F, warm enough that getting in is never a decision. The island is a short ferry ride from Cancún, small enough to cover by golf cart, scooter or bicycle.

The asterisk is the calendar. Anyone reading this has already picked the island, so what is left is the date. September answers with warm water, daytime heat that has started to ease from August, and rain climbing steadily toward October.

On this page

• Isla Mujeres weather in September93.6°F highs, 76.3°F lows and 15.1 rain days
• Can you swim in September?Sea at 87.1°F and the calm side at Playa Norte
• How busy and expensive is September?Ferry rules, the 5% lodging tax and Visitax
• Things to do in SeptemberPlaya Norte, Punta Sur, Garrafon and Isla Contoy
• Isla Mujeres itinerary for SeptemberTwo days around a 6:50 p.m. sunset
• September vs August and OctoberHighs, rain days and sea temperature for the three months
• Is September a good time to go?Who should book it and who should shift

September sits inside the Atlantic hurricane season, which runs June 1 to November 30 and peaks on September 10, with most activity between mid-August and mid-October. Check the National Hurricane Center’s outlook before you fly and again before any boat day.

Isla Mujeres weather in September

The air normals here come from Mexico’s national weather service, the Servicio Meteorológico Nacional, using its 1991-2020 normals for station 23155 in Cancún. That thermometer is on the mainland about 8 miles across the channel. It is the nearest official one, because no station on the island publishes normals. Read the numbers as the mainland’s September, close to the island but not on the beach itself: an average high of 93.6°F, an average low of 76.3°F and 7.15 inches of precipitation.

The SMN counts 15.1 days of measurable rain in an average September, roughly every other day. Its station sheet does not publish the threshold behind “measurable” or say how long or how hard it rained, so compare the figure with a U.S. rain-day tally only loosely. Keep one shade or indoor slot in every day, such as a long lunch in town, and rain becomes a rearrangement.

The 93.6°F average high and 76.3°F average low leave a spread of 17.3°F. Nights hold at 76.3°F, so no warm layer is needed. Pack light shirts, a sun hat, swimwear that dries quickly and a thin rain shell for those 15.1 wet days.

Daylight lasts about 12 hours 18 minutes on September 15. The sun rises at about 6:33 a.m. and sets at about 6:50 p.m., Cancún time. Put the sea in the hours after sunrise and the clifftop views in the last hour before 6:50 p.m.

Can you swim in Isla Mujeres in September? Sea temperature

The sea surface off Isla Mujeres averages 87.1°F in September. That is the mean of daily maxima over 2015-2024 from the Open-Meteo Marine API, so it runs a shade warmer than a 24-hour average would. On the same measure August reads 87.0°F and October 85.9°F.

Set against August’s 87.0°F the water is unchanged for anyone getting in, and October takes 1.2°F off. For the calmest entry, head to Playa Norte. It faces the north tip of the island, where the current running along the east side breaks.

We hold no wind or swell series for September, so we give no wave heights and no odds on flag colors. A passing system near the September 10 peak would be the thing to change the water, and the National Hurricane Center’s outlook is where to read it.

How busy is Isla Mujeres in September? Crowds and prices

We found no occupancy series and no monthly room-rate series for the island, so we place September on no price ladder and count no crowd. What we can state from the calendar is that the month falls in the middle of the hurricane window, with the most active weeks running from mid-August to mid-October.

Ultramar ferry tickets to Isla Mujeres are valid for six months from purchase and are non-refundable. Passengers are asked to arrive 30 minutes before departure. Children under 1.20 meters ride at a reduced fare, and infants under 12 months travel free with a boarding pass. We have no verified booking lead time for rooms, so we give no number of weeks.

Quintana Roo’s lodging tax, the Impuesto Sobre Hospedaje, is 5% of the billed accommodation value, or 6% when a host or booking platform collects payment for a short-term rental (Ley del Impuesto al Hospedaje, art. 8). Separately, every foreign visitor entering Quintana Roo owes the state’s Visitax, 2.50 UMA, about 293 pesos at the 2026 daily UMA value.

The one place extra money changes September is a room with free cancellation. Pay the premium for it, and buy the non-refundable ferry ticket last, once your dates are firm.

Things to do in Isla Mujeres in September

September puts the sea at 87.1°F, so the plans that lead are the wet ones: a swim, a reef day, a boat trip. Highs of 93.6°F push walking into the early and late hours. Most visitors get around by golf cart, scooter or bicycle rather than by car, and the main town is walkable. For where to sleep and how the island fits together, our Isla Mujeres guide takes over.

Playa Norte is the calm-water beach, on the north tip. Punta Sur, at the southern tip, is a clifftop park with a sculpture garden and a lighthouse overlooking open water. Garrafon, a private reef park on the south end, is commonly sold as a snorkeling and activities day pass. Boat trips to Isla Contoy, a national park and bird sanctuary north of the island, are commonly sold from Isla Mujeres. CONANP’s page for the park did not load, so we state no visitor limits.

The air is what moves across the season: 95.2°F highs in August, 93.6°F in September, 90.0°F in October. That gap decides how comfortable the Punta Sur clifftop over open water is in the middle of the day, so save it for early or late.

We hold no verified entry fee for Punta Sur, and Garrafon’s own site did not load, so we quote no admission price and label none of these places free. Walking the town needs no ticket. Ask the operator for the price and the terms before you book.

Isla Mujeres itinerary for September

Cross early. Ultramar boats reach the Terminal Marítima APIQROO on the island from Puerto Juárez, Playa Tortugas (kilometer 6.5 of Boulevard Kukulcán) or Playa Caracol (kilometer 9.5), and you should be at the pier 30 minutes before departure. Swim at Playa Norte first, while the air is under its 93.6°F average high, then spend the hottest hours at a table in town. Rent a golf cart for Punta Sur in the last hour of light, since the sun sets at about 6:50 p.m. on September 15.

Day two is the water day. Book Garrafon’s reef pass or a boat to Isla Contoy, and confirm Contoy’s limits and fees with the operator first. Rain touches about every other day, so if the morning turns gray, swap: town and Punta Sur on the wet day, the reef on the next clear one. On the evening before any boat day, read the National Hurricane Center’s outlook.

Isla Mujeres in September vs August and October

Highs step down from 95.2°F in August to 93.6°F in September and 90.0°F in October. Rain climbs faster, from 4.02 inches over 11.6 days in August to 7.15 inches over 15.1 days in September and 10.91 inches over 17.6 days in October. The air figures share one source and period, SMN station 23155 for 1991-2020. The sea readings come from the Open-Meteo Marine API for 2015-2024: 87.0°F, 87.1°F and 85.9°F.

Shift to October and you gain 3.6°F off the average high, but you take on 2.5 more rain days, 3.76 inches more rain and a sea 1.2°F cooler. Shift back to August and you gain 3.5 fewer rain days, but the high rises 1.6°F. Both neighbors sit inside the hurricane window, so moving a month does not leave the season.

Is September a good time to visit Isla Mujeres?

Yes, if you want water at 87.1°F and can live with 93.6°F highs, measurable rain about every other day and a hurricane-season calendar. It suits anyone whose dates can move or whose room cancels for free. It suits fixed dates and non-cancellable bookings poorly, because the season peaks on September 10 and the ferry ticket cannot be refunded.

For a drier stay, August has 4.02 inches and 11.6 rain days, at the price of 95.2°F highs and the same hurricane window. October is wetter still, at 10.91 inches. To leave the window entirely, remember it ends November 30 and look at the later months in our month-by-month guides.

September’s edge is the combination: highs already 1.6°F below August’s, with the sea still at 87.1°F, a shade above August’s 87.0°F.

The last word

September on Isla Mujeres comes down to one question: can your plans bend? If they can, you get an 87.1°F sea on an island small enough for a golf cart. Read the U.S. State Department’s Mexico Travel Advisory, reissued May 29, 2026, which rates Quintana Roo Level 2, “Exercise increased caution.” Then book a cancellable room, and check the National Hurricane Center’s outlook the day you buy the ferry ticket.

Sources & data for this guide

• Air normals (September, August, October) · Servicio Meteorológico Nacional (CONAGUA), normales climatológicas 1991-2020, station 23155 (Cancún, Benito Juárez) · checked Sep 30, 2026 · nearest official station, no island station publishes normals · rain-day threshold not published on the SMN sheet
• Sea surface temperature · Open-Meteo Marine API, mean of daily maxima 2015-2024 · checked Sep 30, 2026
• Daylight and sunrise/sunset on September 15 · sunrise-sunset.org (UTC times converted to America/Cancun) · checked Sep 30, 2026
• Hurricane season dates and September 10 peak · NOAA National Hurricane Center, nhc.noaa.gov · checked Sep 6 and Sep 29, 2026
• Ferry terminals and ticket rules · Ultramar, “Ferry Isla Mujeres” · checked Sep 30, 2026
• Lodging tax · Ley del Impuesto al Hospedaje del Estado de Quintana Roo, art. 8, congresoqroo.gob.mx · checked Sep 30, 2026
• Visitax · Ley de Derechos del Estado de Quintana Roo, art. 51-Octies, congresoqroo.gob.mx · checked Sep 30, 2026
• Travel advisory · U.S. Department of State, travel.state.gov, Mexico Travel Advisory reissued May 29, 2026 · checked Sep 30, 2026
• Editorial note · Garrafon’s site and CONANP’s Isla Contoy page did not load on Sep 29, 2026, so no fees or visitor limits are given. We found no occupancy, room-rate, wind or swell series and no verified September event dates, so none appear. Place descriptions are common knowledge.