LA PAZ · SEPTEMBER · BAJA CALIFORNIA SUR
La Paz in September is a swimming month. The bay sits at 87.1°F, afternoons average 96.6°F, and the malecon gets 12 hours 19 minutes of daylight at mid-month.
The other side of that warm water is rain: 3.20 inches over the month, the wettest of the three around it at that figure, spread over 6.3 days. September also ends the day before the whale shark season in the bay opens on October 1, 2026.
THE MONTH AT A GLANCE · LA PAZ
September in La Paz brings 96.6°F afternoons, 3.20 inches of rain and an 87.1°F sea, and it closes one day before the whale shark season opens on October 1.
AVERAGE HIGH 96.6°F · SEA 87.1°F · 6.3 RAIN DAYS · WHALE SHARK SEASON OPENS OCT 1
Go for: swimming in a sea at 87.1°F (the warmest of August, September and October), boat days to Isla Espiritu Santo, and evening walks on the malecon.
Think twice before: booking for whale shark swimming, because the 2026-2027 season opens October 1, 2026, after September ends.
Climate: SMN (CONAGUA) station 03074 · Sea: Open-Meteo Marine API · Daylight: sunrise-sunset.org · full sources below
On this page
- La Paz weather in SeptemberHighs, lows and 6.3 rain days
- Can you swim in La Paz in September?Sea temperature: 87.1°F
- How busy is La Paz in September?Crowds, the 4% lodging tax and booking
- Things to do in La Paz in SeptemberIsla Espiritu Santo, the malecon and whale shark dates
- La Paz itinerary for SeptemberTwo days, hour by hour
- La Paz in September vs August and OctoberAugust at 100.0°F, October at 93.2°F
- Is September a good time to visit La Paz?Who should go, and who should pick October
One planning fact sits outside the weather. The U.S. State Department’s Mexico travel advisory, reissued May 29, 2026, rates Baja California Sur at Level 2, exercise increased caution, due to terrorism and crime, and sets no specific restrictions on travel for U.S. government employees in the state. Our Travel 101 section covers general trip preparation.
La Paz weather in September: average highs, lows and rain days
| Measure | September average | Source |
|---|---|---|
| Average high | 96.6°F | SMN station 03074, 1991-2020 |
| Average low | 76.5°F | SMN station 03074, 1991-2020 |
| Precipitation | 3.20 inches | SMN station 03074, 1991-2020 |
| Days with measurable rain | 6.3 days | SMN station 03074, 1991-2020 |
| Daylight on Sept 15 | 12 h 19 min | sunrise-sunset.org |
| Sunrise / sunset on Sept 15 | 6:06 a.m. / 6:25 p.m. | sunrise-sunset.org, local time |
Every air temperature and rain figure here comes from the 1991-2020 normals of Mexico’s national weather service (SMN, part of CONAGUA), taken at its own La Paz station, number 03074 (DGE), in town. They describe the malecon and the bay. We have no thermometer out on the islands. In September the average high is 96.6°F, the average low 76.5°F, and precipitation totals 3.20 inches.
The SMN counts 6.3 days of measurable rain in an average September, roughly one day in five (its sheet does not publish the threshold for “measurable”). An average hides the spread, so treat any single day as a one-in-five chance of a shower and keep one day in the plan loose enough to swap.
Afternoons and nights sit 20.1°F apart, yet the low stays at 76.5°F. Nothing cools enough to call for a jacket. Pack light breathable clothes, a hat and swimwear, and bring a thin layer only for air-conditioned rooms.
On September 15 the day runs 12 hours 19 minutes, with sunrise near 6:06 a.m. and sunset near 6:25 p.m. (converted to America/Mazatlan time, La Paz’s zone). Sunset at 6:25 p.m. leaves little light for a late start on the water. Put beach and boat time early and leave the middle of the day for shade.
Can you swim in La Paz in September? Sea temperature
The Open-Meteo Marine API puts the sea surface off La Paz at 87.1°F in September, averaged over 2015-2024. That figure is a mean of daily maxima, a shade warmer than a 24-hour mean, and it comes from a marine data series rather than a thermometer at a particular beach.
Swimming is comfortable. The sea sits 9.5°F under the average afternoon high of 96.6°F, so a dip cools you without a shock, and it stands 10.6°F above the 76.5°F overnight low, so the water still feels warm at dusk. Expect a shorts-and-mask swim, not a wetsuit one.
We have no wind or swell series for September, so we cannot say how choppy the bay runs. Boat operators judge that day by day. Ask the morning you sail, and use the loose day from the weather plan for exactly that.
How busy is La Paz in September? Crowds and prices
We found no occupancy series and no monthly hotel rates for La Paz, so we crown no month expensive or cheap and place September in no price ranking. The calendar does give one fixed point: the whale shark season in the bay opens October 1, 2026, and runs to April 30, 2027.
We also found no data on how far ahead rooms fill, so we give no lead time in weeks. The airport gives scale only: La Paz International (LAP) recorded 1,337,600 passengers in 2025, a yearly total with no monthly split. If whale shark swimming is the goal, book for October or later rather than September.
Baja California Sur’s lodging tax (the Impuesto sobre la Prestacion de Servicios de Hospedaje) is 4% in 2026, set by article 13 of the state’s Ley de Hacienda. Ask whether a quoted room rate already includes it before comparing two hotels.
The one line where paying more changes the month is cooling. With a 76.5°F average low, nights stay warm, so a room with reliable air conditioning does more for your sleep than a bay view does.
Things to do in La Paz in September
September falls before the whale shark season. SEMARNAT’s notice of September 17, 2026 sets the 2026-2027 season in the Bahia de La Paz refuge from October 1, 2026 to April 30, 2027, so a September trip is a bay-and-islands trip. Whale shark swimmers should take October.
Isla Espiritu Santo, in the Bay of La Paz, has been a national park since 2007 and part of the UNESCO World Heritage Site “Islands and Protected Areas of the Gulf of California” since 2005. It is the day-boat target. The malecon is the bayfront promenade in town. We could not verify park fees, operator prices or departure times, so we give none. Confirm them when you book.
Across August, September and October the sea holds within 1.5°F (85.6°F in October to 87.1°F in September, all from the marine API), while the air falls 6.8°F from August’s 100.0°F high to October’s 93.2°F. The air moves far more than the water, so plan the boat day around the heat: morning out, shore or shade by the afternoon.
The malecon is a public promenade, so a walk there costs nothing, and the last light before the 6:25 p.m. sunset is the time to take it. We have no verified list of free-entry days at any site in September.
La Paz itinerary for September
Day one, in town. Start on the malecon at first light, when the sun rises near 6:06 a.m. and the air is at its coolest, then take a long breakfast. Spend the middle of the day indoors while the average high reaches 96.6°F. Return to the bay for a swim in late afternoon, in water at 87.1°F, and finish with a walk along the front before the 6:25 p.m. sunset.
Day two, on the water. Take a boat toward Isla Espiritu Santo in the morning, swim off the boat, and be back on shore before the afternoon high. If the forecast turns wet (6.3 rain days in an average September), swap the two days so the town day takes the rain. Book the island day directly with an operator, as we have no verified prices or schedules.
La Paz in September vs August and October
| Average | August | September | October |
|---|---|---|---|
| High | 100.0°F | 96.6°F | 93.2°F |
| Low | 77.4°F | 76.5°F | 70.2°F |
| Precipitation | 1.79 inches | 3.20 inches | 0.68 inches |
| Days with measurable rain | 6.3 | 6.3 | 1.8 |
| Sea surface (marine API, 2015-2024) | 86.1°F | 87.1°F | 85.6°F |
August is the hotter neighbor: 3.4°F higher than September on the average high, 0.9°F higher on the low, with a sea 1.0°F cooler. October is the cooler one: 3.4°F lower on the high, 6.3°F lower on the low, with a sea 1.5°F cooler. Rain drops sharply into October, from 3.20 inches to 0.68 inches and from 6.3 rain days to 1.8. September shares August’s 6.3 rain days but brings 3.20 inches against 1.79 inches.
Moving to October trades 1.5°F of sea warmth for a much drier stay (0.68 inches, 1.8 rain days), nights near 70.2°F and the whale shark season already open. Moving to August means 100.0°F highs against September’s 96.6°F, less rain at 1.79 inches, and a sea 1.0°F cooler. Rain worry points to October, and heat worry points away from August.
Is September a good time to visit La Paz?
For most warm-weather travelers, yes: an 87.1°F sea, mornings and late afternoons outdoors, and the middle of the day in shade or water. It suits less well anyone set on whale shark swimming, anyone bothered by 3.20 inches of rain in a month, or anyone who wants a cool evening when the average low is 76.5°F.
October is the month to prefer if the answer is no. It opens the whale shark season (October 1, 2026 to April 30, 2027, under a federal plan covering three seasons between 2026 and 2029) and brings the drier air of 0.68 inches. For other dates, our Where to Go by month pages cover the calendar.
Among August, September and October, September has the warmest sea at 87.1°F, with the whale shark season still ahead.
The last word
If the bay itself is the point, September’s water is ready for you. If whale sharks are the point, book October 1 or later. For the trip onward, Baja Ferries sails La Paz to Topolobampo Monday through Friday, with check-in at 12:00, departure at 13:30 and arrival at 20:30. The Saturday sailing checks in at 21:30, departs at 23:00 and arrives at 08:00 the next morning.
Sources & data for this guide
- Climate normals 1991-2020 (air temperature, precipitation, rain days) · Servicio Meteorologico Nacional (CONAGUA), station 03074, La Paz (DGE) · checked Sep 30, 2026
- Sea surface, mean of daily maxima 2015-2024 · Open-Meteo Marine API · checked Sep 30, 2026
- Daylight, sunrise and sunset on September 15 (13:06 UTC and 01:25 UTC, converted to America/Mazatlan time) · sunrise-sunset.org · checked Sep 30, 2026
- Whale shark refuge, 2026-2027 season · SEMARNAT official notice of Sept 17, 2026, gob.mx · checked Sep 30, 2026
- Isla Espiritu Santo status · CONANP and UNESCO (2005 inscription), corroborated by El Sol de Mexico · checked Sep 30, 2026
- Lodging tax, 4% in 2026 · Ley de Hacienda del Estado de Baja California Sur, art. 13 · checked Sep 30, 2026
- Airport passengers, 2025 · Grupo Aeroportuario del Pacifico, La Paz page · checked Sep 30, 2026
- Ferry schedule · Baja Ferries, Rutas y Horarios · checked Sep 30, 2026
- Travel advisory · U.S. Department of State, Mexico advisory reissued May 29, 2026 · checked Sep 30, 2026
- We found no occupancy series, monthly hotel rates, wind or swell data, event dates for September, or verified park fees and boat prices, so we give none. Operators change hours and prices · check when you book.