Going to the Caribbean at the end of summer? If you know what to expect for Cartagena weather in September, you can make more informed plans ahead of your arrival. September is hot, humid, and the month in which Cartagena rains the most. The chances of rain are good, but don’t be afraid to spend all your time indoors. You can still get warm tropical conditions and very warm Caribbean water. The important thing is to be flexible with your schedule and follow your daily weather forecast.
Beaches, the Rosario Islands, historic streets, boat trips, and other attractions are on your list, this guide will help you understand what September is really like and how you can plan around the weather.
Cartagena Weather in September at a Glance
Cartagena weather in September remains warm during the day and night. Average daytime highs are around 30–31°C (86–88°F), while nights usually remain close to 26–27°C (79–81°F). The sea is even warmer at around 29–30°C (84–86°F).
| Weather Factor | What to Expect in September |
| Average daytime high | Around 30–31°C (86–88°F) |
| Average nighttime low | Around 26–27°C (79–81°F) |
| Sea temperature | Around 29–30°C (84–86°F) |
| Humidity | High, often around 77–82% |
| Rainfall | Frequent tropical rainfall is possible |
| Rainy period | September falls within the wetter part of the year |
| Daylight | Around 12 hours |
| UV levels | High |
| Overall conditions | Hot, humid, warm sea, with regular chances of rain |
Rainfall totals differ among datasets, as climate sources employ different observation periods. The most important thing for your journey is that September has some real possibility of rain, and the temperatures and sea conditions are still very warm.
What the Weather in Cartagena Colombia in September Really Feels Like
Although it is helpful to look at the numbers, it does not reveal the overall feeling of the weather outside. The weather in Cartagena Colombia in September feels very tropical. The heat and humidity will be noticed right away. Light clothing, ample water and breaks in the heat of the day can help you be more comfortable while exploring.
September Temperatures and Tropical Heat
Don’t be concerned by the cold weather here. The average highs are around 30-31°C and the temperatures at night remain in the upper 20s Celsius. That heat is increased by humidity. It may be hot after a short walk in the Old City, particularly during the middle of the day. Try exploring early in the morning or later in the afternoon. When outside at midday, take regular breaks and carry water.
Humidity and Sunshine During September
High humidity is a normal part of weather in Cartagena in September. Climate data indicate that average relative humidity in the upper 70s to low 80s. Sun protection is not something that is automatically taken care of when it’s cloudy. Sunscreen, sunglasses and hat should be in your day bag as exposure is strong. It is also possible that, if the morning is cloudy, it will become sunny later in the day, or else it may not be sunny at all. This is one of the reasons why the flexible plans are so effective in September.
Warm Caribbean Sea Temperatures
September has one thing going for those who enjoy warm water, it’s the weather. The sea temperature is generally around 30°C (86° F). This makes the Caribbean pleasant for swimming, snorkeling and activities around the islands. But it is not always warm water, it is also calm water. Waves and visibility may be influenced by wind, rain and local storms. Check the sea state before going out to sea.
Rainfall Patterns in Cartagena During September
The top thing you’ll want to watch out for during Cartagena Weather in September is of course the rain. Don’t take it lightly but don’t think that it’s going to spoil the trip. September is one of the wettest months in Cartagena.
Historical data show a range of values for the total rainfall during the month, but consistently, rain is much more likely than during dry-season months. If you want to see an even larger seasonal overview, you can use our cartagena weather guide to pick a travel time.
How Much Does It Rain in September?
Precipitation values depend on the climate data set and the period of reference. According to Weather Atlas, September receives 150 mm of precipitation, for instance, and Climate-Data.org lists a higher historical monthly average.
Don’t expect it to be exactly one day in a seven-day period, but rather get ready for a chance of rain. Bring an umbrella or light rain jacket along. More importantly, check the daily and hourly forecast once you are in Cartagena.
Does Rain Last All Day?
Rainy days do not have to be all day from morning till night. The weather in the tropics can turn around in a blink. It is possible to receive dry spells, clouds, sunshine, and showers all in one day. Other days there can be unsettled weather for some time.
Don’t assume that all showers will be gone in a few minutes and schedule your trip accordingly. Make decisions based on the most current local forecast.
Morning vs Afternoon Weather
Not all September mornings are sunny, nor all September afternoons rainy. Instead, check the hourly forecast before you leave your hotel. When the best weather is forecasted in the early hours, go out to see the sights or enjoy water sports.
When the weather doesn’t sound great, reserve indoor attractions, restaurants, museums and shopping.
September as a Good Time to Visit Cartagena
The best time to visit Cartagena will depend on the type of holiday you are looking to take. September is not a dry season month but still has the tropical heat and very warm Caribbean sea water.
Benefits of Visiting Cartagena in September
If you’re willing to make some adjustments, September is a good month. The temperature of the sea is maintained high and swimming and activities on islands remain appealing when the sea is safe. There is also more to explore in Cartagena. Enjoy the colourful streets, local food, historic sites or time around the bay. Traveling with children? Check out these things to do in Cartagena with family and mix in some indoor with outdoor.
Things to Consider Before Visiting
Rain and humidity are the two main things to prepare for. Walking for extended periods can be hot. Outdoor plans or marine conditions can also be impacted. Do not plan all hours of all days! Some flexibility in the schedule will make it easier to shift activities when the weather turns bad.
September Compared With August
The September weather isn’t a huge drop from August, either, as it is still warm and wet. The historical averages from Timeanddate are very similar for the two months respectively. If you are unsure of which one to choose, read our full guide to the Cartagena weather in August.
Best Boat Trips in Cartagena During September
Never restrict yourself with only one type of boat experience. Cartagena weather in September is unpredictable, so it’s easier to plan because of multiple options.
Private Rosario Islands Speedboat Trip
When you are looking to visit the Rosario Islands, a Private speedboat Rosario Island trip will provide you with a more private and comfortable day. Enjoy the Caribbean ambiance and have fun on the water without the crowds of large tour groups. Always check the latest weather and marine conditions before departure.
Private Boat Charter for Your Group
Traveling with family or friends? A Private boat charter Rosario Island tour is a convenient and exclusive way for your group to explore the Caribbean. You can enjoy beautiful island views, spend time swimming and enjoy each other’s company on the water when the weather and sea conditions are favourable.
Cartagena Sunset Catamaran
A full day Cartagena island trip is not always mandatory. A Cartagena sunset catamaran lets you experience the city and bay around sunset. Always check weather forecasts before heading out, particularly in September.
Cartagena Bay Dinner Cruise
Looking for something more laid back in the evening? A Cartagena bay dinner cruise offers a waterfront sighting, while also serving dinner. If you’re still looking to see what suits your time, check Cartagena boat tours and compare experiences.
What to Pack for Cartagena in September
Preparing for Cartagena Weather in September is easy, just make sure you’re ready for some heat, humidity, sunshine and rain.
Bring:
- Wear light clothes: Light shirts, dresses, shorts, and loose trousers.
- Swimwear: Bring at least one swimsuit for beaches, pools and trips to the islands.
- Waterproofing: A small umbrella or lightweight rain jacket will come in handy.
- Sun protection: Carry sunscreen, sunglasses, and a hat.
- Comfortable shoes: Choose shoes that can handle warm weather and occasional wet streets.
- Waterproof pouch: Keep your phone, cash and documents protected on boat days.
- Refillable bottle: Staying hydrated is important in Cartagena’s humidity.
- Rainwear: This is useful after it rains, swimming or performing boat activities.
Don’t stuff just heavy clothing. The temperature remains warm even during rainy days in Cartagena.
Practical Tips for September Weather in Cartagena
The best answer to the question “What is the weather like in Cartagena Colombia in September?” is hot, humid and changeable, and there’s a real possibility of precipitation.
Here are a few tips that make traveling easier:
- Review the forecast daily: Use hourly forecasts, not monthly forecasts.
- Be flexible: schedule outdoor activities during a window of clearer weather.
- Stay hydrated: Heat and humidity can rob you of your energy more quickly than you realize.
- Avoid too much midday walking: Explore early or later when possible.
- Take a small umbrella: It can save you from returning to your hotel.
- Look at sea conditions: Wind and waves are just as important as rain for boat trips.
- Follow your captain’s lead: Refuse the trip to the islands if marine conditions are not favorable.
- Maintain back-up activities: Food tours, museums, restaurants, shopping, and historic sites are good ways to fill wetter periods.
Final Thoughts
Cartagena weather in September is hot, humid and wetter than the dry season months, but this should not discourage you from visiting Cartagena. The Caribbean is still very warm and there are chances for beaches, sightseeing, sailing and adventures in the Rosario Islands. The key is to be flexible and work with existing conditions.
Monitor weather forecast daily and watch marine weather before going offshore. When the weather looks good, explore Cartagena all tours to find a boat experience that suits your plans. For assistance in selecting an option for your September holiday, send us a message via WhatsApp and make your trip on water even more exciting and successful!
Frequently Asked Questions
What Is the Weather Like in Cartagena Colombia in September?
September is hot and humid, with daytime highs averaging 30–31°C and warm nights at 26–27°C, and rain is likely as the rainy season continues during the month.
How Hot Is Cartagena Weather in September?
Daytime temperatures are expected to be around 30-31°C (86-88F). During the day time strolls, humidity can make the heat seem more intense. Nights are also warm.
Can You Visit the Rosario Islands in September?
Yes, island trips are run when weather and sea conditions are favorable. Check the latest wind, rain, and sea forecast before departure and follow your captain’s advice.
Is September the Best Time to Visit Cartagena?
If you can handle tropical rain and are not bound by your plans, then it can be a good month. Weather remains warm and Caribbean Sea temperatures are quite warm and activities possible if conditions are favorable.