#1Hot
Puerto Vallarta
- Day
- 30.4°C
- Sea
- 29.7°C
- Sun
- 2.0h
- Rain days
- 28
Your September weather guide
Weather in Mexico in September
September is a reasonable month for Mexico if you want warm seas and can work around frequent rain, but it is a poor fit for a sunshine-first beach holiday. Average daytime temperatures reach 30°C, nights stay at 25°C, and rain occurs on 25 days. The choice between these coastal destinations is less about finding heat than balancing wet days against warm evenings. Keep outdoor plans flexible rather than relying on settled weather.
Long-term climate averages, not a forecast · 1991-2020
- Average daytime high
- 29.7°Cacross 5 destinations
- Average night-time low
- 25.4°Cafter dark
- Sea temperature
- 29.3°Cwarm enough to swim
- Rainy days
- 25days1 mm or more
Mexico, month by month
Turn up the warmth
Warmest places in Mexico in September
Ranked by average daytime high. The full comparison is in the table below.
#2Hot
Riviera Maya
- Day
- 29.6°C
- Sea
- 29.2°C
- Sun
- 4.3h
- Rain days
- 24
#3Hot
Tulum
- Day
- 29.6°C
- Sea
- 29.2°C
- Sun
- 4.3h
- Rain days
- 24
#4Hot
Playa del Carmen
- Day
- 29.5°C
- Sea
- 29.3°C
- Sun
- 4.3h
- Rain days
- 25
#5Hot
Cancun
- Day
- 29.3°C
- Sea
- 28.9°C
- Sun
- 4.6h
- Rain days
- 25
Mexico destinations ranked for September
All 5 places we track in Mexico, ordered by daytime high.
Scroll sideways for more weather, down for more places. Click a heading to sort.
| # | Destination | ||||||
|---|---|---|---|---|---|---|---|
| 1 | Puerto Vallarta | 30.4°C | 24.2°C | 29.7°C | 2.0 h | 28 | 12 h 18 min |
| 2 | Riviera Maya | 29.6°C | 25.6°C | 29.2°C | 4.3 h | 24 | 10 h 48 min |
| 3 | Tulum | 29.6°C | 25.6°C | 29.2°C | 4.3 h | 24 | 10 h 54 min |
| 4 | Playa del Carmen | 29.5°C | 25.6°C | 29.3°C | 4.3 h | 25 | 10 h 48 min |
| 5 | Cancun | 29.3°C | 25.8°C | 28.9°C | 4.6 h | 25 | 10 h 42 min |
5 destinations shownClimate averages, not a forecast.
September climate overview
Daytime highs across Mexico in September run from 29.3°C (Cancun) to 30.4°C (Puerto Vallarta). In Puerto Vallarta about 100% of September days reach 25°C. Nights average 25.4°C; the coldest 10% of nights in Cancun fall to 25°C or below.
Rainfall in September
Expect around 25 rainy days (1 mm or more) in September, with Tulum the driest (24 days) and Puerto Vallarta the wettest (28 days). The wettest September at Puerto Vallarta between 1991 and 2020 was 2000 with 551 mm; the driest was 2018 with 197 mm.
Sea temperature
The sea averages 29.3°C around Mexico in September - warmest at Puerto Vallarta (29.7°C). That is comfortable for swimming.
Sunshine and daylight
Around 3.9 hours of sunshine a day on average, out of 12.1 hours of daylight (sunshine estimated from cloud cover).
September against the rest of the year in Mexico
September is the 4th warmest month of the twelve in Mexico. It is 0.6°C cooler than August and 0.9°C cooler in October. The hottest month here is August (30°C) and the coolest January (26°C).
Which part of Mexico in September?
- Most sunshine: Cancun, 4.6 h a day.
- Driest: Tulum, about 24 rainy days.
- Warmest sea: Puerto Vallarta, 30°C.
- Hottest: Puerto Vallarta, 30°C by day.
- Coolest (better for walking and cities): Cancun, 29°C.
What to pack for Mexico in September
Based on the averages: summer clothes for the day; a rain jacket - roughly 25 wet days; swimwear - the sea is 29°C.
Similar weather elsewhere in September
Within 1.5°C of Mexico's September daytime average: Marrakech (31°C), Montego Bay (31°C, sea 30°C), Bangkok (31°C, sea 29°C), Sousse (31°C, sea 26°C), Seville (30°C). See the full ranking for September.
Which part of Mexico should you choose?
Riviera Maya and Tulum offer the better balance if fewer rainy days are your priority: both have 24, alongside daytime temperatures of 30°C. That is still frequent rain, so neither is a dry-weather choice. Playa del Carmen has similar warmth but slightly more rainy days, while Cancun is marginally cooler at 29°C, with 25 rainy days. Puerto Vallarta suits travellers who put very warm water ahead of drier conditions: its sea reaches 30°C, but rain occurs on 28 days. There is no clear dry option among these destinations, and the small temperature differences are unlikely to decide the trip as much as your tolerance for rain.
What the weather means for your plans
Pack for persistent warmth rather than cool evenings: light clothing, something breathable to sleep in and a lightweight waterproof are sensible choices. With average sunshine of 3.9 hours, September is not the month to build every day around sunbathing. Keep outdoor time movable and leave room to change plans when rain arrives; the rainy-day figures do not tell you how long each spell lasts. Daytime warmth is well above London's September average of 19°C, so allow yourself shade and breaks around midday rather than treating cloudy weather as cool weather. The sea averages 29°C, making water temperature a stronger reason to visit than the promise of uninterrupted sunshine.
A little more detail
Mexico in September FAQs
Plain answers, grounded in the averages.
Where is the hottest place in Mexico in September?
Puerto Vallarta is the warmest of the 5 places we track in Mexico in September with an average high of 30.4°C; Cancun is the coolest at 29.3°C.
Is the sea warm in Mexico in September?
The sea averages 22°C or more at Puerto Vallarta (30°C), Riviera Maya (29°C), Tulum (29°C), Playa del Carmen (29°C), Cancun (29°C) in September.
Is the sea warm enough for swimming in September?
Yes, sea temperatures are warm across these destinations: 30°C in Puerto Vallarta and 29°C in Riviera Maya, Tulum, Playa del Carmen and Cancun. Cold water is unlikely to be the drawback, though warm water alone does not establish safe swimming conditions.
Will I need warm clothes in the evening?
Outdoor evenings remain warm, with night temperatures of 24°C in Puerto Vallarta and 26°C in the other listed destinations. Light clothing should be the starting point for packing rather than heavy layers. Rain protection is likely to be more useful than clothing for cold nights.
Which destination has the fewest rainy days?
Riviera Maya and Tulum have the fewest rainy days at 24, compared with 25 in Cancun and Playa del Carmen and 28 in Puerto Vallarta. That makes them relatively better choices for avoiding rain, not reliably dry choices.
About these averages
ERA5-Land climate reanalysis via Open-Meteo (11 km grid), 1991-2020
Averages computed from daily values at 5 destination points.Records are the highest and lowest daily values in that 30-year period, not all-time records. These are climate averages, not a forecast for your trip. How we measure holiday weather
- Hot · 25°C+
- Warm · 20°C to below 25°C
- Mild · 15°C to below 20°C
- Cool · below 15°C