When you picture summer in Cotonou, you probably imagine warm days, thick humidity, and those sudden rain showers that can pop up and change your plans in a heartbeat. Daytime temperatures usually stick around the mid-80s to upper 80s °F (about 29–31°C), and nights stay toasty near 75–78°F (24–26°C). The heat feels steady, and the humidity really adds to that tropical vibe.
Rain shapes summer life here. June often delivers the heaviest downpours, and rainy days can really mess with outdoor plans. By July and August, the rain lightens up a bit, though it never totally stops, so you’ll see a mix of wet stretches and some drier days.
Sunshine hours drop, but the sea stays warm and inviting, with water temperatures near 26–28°C (79–82°F). The ocean’s always tempting, even when the sky looks a bit gloomy.
This blend of heat, rain, and salty breezes really defines the season. If you’re planning to explore, hit the beach, or just want to know what to expect, understanding these patterns will help you enjoy your time in Cotonou.
Overview of Cotonou’s Summer Climate
Cotonou’s summers bring steady warmth, high humidity, and plenty of rainfall that slowly eases as summer goes on. You’ll get a mix of hot days, cloudy skies, and breezy evenings, all shaped by its tropical savanna climate and coastal spot.
Tropical Savanna Climate Characteristics
Cotonou sits in a tropical savanna climate (Aw classification), so it keeps warm temperatures all year with clear wet and dry seasons. In summer, daily highs typically range from 82°F to 86°F (28°C to 30°C), and lows hang around 75°F to 76°F (24°C).
Humidity rarely lets up, often pushing close to 100% muggy conditions. The Atlantic nearby keeps temperatures a bit more stable, but it also adds to that sticky feeling in the air.
Clouds often fill the sky, but things start to clear as summer moves on, dropping from about 81% overcast in early summer to 65% by late summer. You’ll get a bit more sun later, though the heat doesn’t really fade.
Cotonou doesn’t have a traditional growing season since the warmth and rain stick around. Crops and plants grow year-round, thriving on the steady heat and those seasonal showers.
Seasonal Weather Patterns
Summer falls right in the middle of the long rainy season here, but rainfall slowly drops as the months tick by. Early on, you’re looking at a 65% chance of wet days, which dips to about 51% by late summer. Monthly rainfall averages shift from 6.0 inches (152 mm) in June to 3.8 inches (96 mm) in August.
The cloudiest days usually hit in June, but by early August, you’ll see the clearest skies, with up to 37% of the time showing clear or partly cloudy weather. Humidity sticks around, so don’t expect the air to dry out much.
Winds pick up as the season goes, climbing from 8 mph to nearly 10 mph, mostly blowing from the south or west. These breezes make the heat a bit more bearable and help clear out some of those heavy clouds.
Surface water temperatures in the Gulf of Guinea drop a bit, from 83°F to 77°F, and that helps keep the coast more stable than inland spots.
Average Daytime and Nighttime Temperatures
Cotonou stays warm all summer, and day-to-night temperatures don’t swing much. The heat feels steady, but the ocean breeze comes in handy, especially when the sun goes down.
Typical Highs and Lows in Summer
During summer, average daytime temperatures hover around 30°C (86°F). The hottest part of the day can hit 30–31°C, which is warm but not unbearable compared to spots further inland.
At night, temperatures only drop a little. Most nights, you’ll see lows around 26–27°C (79–81°F). It stays muggy, and honestly, you’ll probably want a fan or AC to get comfortable.
Humidity ramps up the heat, especially in June and July when rain is frequent. Even so, those coastal winds help keep things from getting totally overwhelming.
Quick Reference:
- Daytime highs: ~30–31°C (86–88°F)
- Nighttime lows: ~26–27°C (79–81°F)
- Temperature range: Narrow, just a 4–5°C difference
Monthly Temperature Variations
Summer in Cotonou runs from June to August, and the numbers don’t change much between months. In June, daytime highs average about 30°C, with nights near 27°C.
July’s pretty similar, though more clouds and rain can make it feel a little cooler, even if the thermometer doesn’t budge. Highs stay close to 29–30°C, and nights settle at 26°C.
August cools off a bit. Average daytime temperatures drop to around 27°C (81°F), and nights hit about 24°C (75°F). It’s the most comfortable stretch, but yeah, it’s still humid.
Monthly Averages (°C):
| Month | Daytime High | Nighttime Low |
|---|---|---|
| June | 30 | 27 |
| July | 29–30 | 26 |
| August | 27 | 24 |
Rainfall and Rainy Days During Summer
Summer brings some of the heaviest rainfall Cotonou sees all year. Expect frequent showers, high humidity, and a clear shift from really wet months to ones that are just somewhat wet.
Monthly Rainfall Totals
Rainfall peaks in June, with about 259 mm—it’s the wettest month by far. July isn’t far behind, still bringing heavy rain compared to most other times.
By August, rain backs off a bit, averaging closer to 100–120 mm. The trend keeps going into September, though you’ll still see showers.
Here’s a quick look at the averages:
| Month | Rainfall (mm) |
|---|---|
| June | ~259 mm |
| July | ~200 mm |
| August | ~110 mm |
| September | ~120 mm |
You can see how things go from super wet early on to a bit more reasonable as summer winds down.
Frequency of Rainy Days
Rainy days follow the same pattern. June averages about 18 rainy days, so you’re looking at rain more than half the time. Showers can be heavy but often don’t last too long, leaving the air thick afterward.
July keeps up with the trend, usually bringing 12 to 15 rainy days. By August, the count drops, with around 8 to 10 rainy days, so you’ll get more dry spells.
September picks up a little, often with 10 to 12 rainy days. Even though the rain isn’t as intense as in June, the weather can still feel a bit unsettled.
This cycle of rain and breaks creates a humid but livable atmosphere for getting things done.
Humidity and Comfort Levels
Cotonou’s summer is all about high humidity, and it really shapes how you feel outside. The mix of warm temps and thick air makes it feel hotter than what the numbers show.
Average Relative Humidity in Summer
During summer, relative humidity usually stays between 82% and 88%. June tops out near 88%, and July and August don’t drop much.
That much moisture in the air makes it tough for your body to cool off by sweating. Even when it’s around 27–30°C (80–86°F), it can feel a lot warmer.
Humidity barely dips, even in the afternoon. Nights are especially sticky, with levels rarely falling below 80%. This constant dampness is classic for coastal spots like Cotonou, thanks to the Atlantic.
Impact on Daily Life
You’ll notice the humidity in almost everything you do. Walking outside can wear you out quicker, and clothes tend to cling to your skin. Lightweight, breathable fabrics and staying hydrated are a must.
People rely on air conditioning and fans at home, in hotels, and at work to deal with the stickiness. Even with cooling, the air inside can still feel heavy if there’s not much airflow.
Tourists usually find mornings more comfortable for exploring, even though the humidity sticks around. Outdoor workers take more breaks in the shade and try to avoid the hottest part of the day.
High humidity messes with food storage and can make rooms feel damp, since moisture encourages mold. Lots of folks use dehumidifiers or open windows to keep things in check.
Sea Temperature and Coastal Conditions
The coast along the Bight of Benin stays warm all year, with just a few shifts through the seasons. The sea feels warmest in late spring and early summer, then cools a bit by July and August as ocean currents change. These changes matter if you’re into swimming or other coastal activities.
Average Summer Sea Temperatures
During summer, Cotonou’s sea temperatures range from about 26°C (79°F) in July and August up to 29°C (84°F) in May and June.
The sea holds onto heat from the dry season, so it’s warmest in late spring and early summer. By mid-summer, upwelling cools things down, especially in July and August.
| Month | Avg. Sea Temp °C (°F) |
|---|---|
| May | 29 (84) |
| June | 28 (82) |
| July | 26 (79) |
| August | 25–26 (77–79) |
You’ll get warm water all summer, though August’s cooler temps can feel nice when it’s hot out. The changes aren’t huge, but if you’re in the water a lot, you’ll notice.
Swimming and Water Activities
Swimming’s good year-round in Cotonou, and summer is no different. The sea stays warm enough, even at its coolest, that you won’t need a wetsuit.
May and June are perfect for long swims or lazy beach days. By July and August, the water’s a bit cooler, which actually feels pretty refreshing with all the heat and humidity.
Waves along the Bight of Benin usually stay moderate, but sometimes currents get strong. It’s smart to check local advice before swimming far out. For wading or playing near shore, you’ll usually find safe, pleasant conditions.
If you’re into snorkeling or boating, keep in mind that rainfall and runoff in June and July can make the water a bit cloudy.
Wind Speed and Weather Dynamics
During the summer months in Cotonou, steady winds and seasonal shifts in air movement shape the daily weather. These winds affect temperature, cloud cover, and rainfall, and they really change how you experience the city’s climate.
Prevailing Wind Patterns in Summer
From June through early October, you’ll notice the winds pick up compared to other months. Average wind speeds usually top 8 miles per hour, and August really takes the cake, hitting about 10 miles per hour.
These winds mostly come from the southwest, pulling in moist air off the Atlantic Ocean. This steady stream of maritime air keeps feeding the wet season and brings rain-bearing systems right over the city.
You’ll feel the breeze both day and night. Daytime winds feel stronger, but even in the evenings, there’s enough movement in the air to cut through the humidity.
| Month | Avg. Wind Speed (mph) |
|---|---|
| June | ~8.2 |
| July | ~9.0 |
| August | ~10.1 |
| Sept. | ~8.5 |
Every summer, you can count on these wind patterns. They really shape what the season feels like in Cotonou.
Effect on Local Climate
Summer wind patterns shape how hot and sticky it feels outside. Strong breezes help keep the worst of the heat at bay, so daytime highs usually stay near 81–83°F even in the heart of the rainy season.
Moist winds bring in more clouds. That means less direct sun, which keeps temperatures from climbing too high and makes being outside a little less intense than during the dry months.
As this moist air moves inland, it sparks frequent showers. June and September get hit the hardest with rain, thanks to these winds.
So, if you spend summer in Cotonou, expect it to feel humid, breezy, and often cloudy. Rain showers pop up often but don’t usually last long. The wind keeps the air moving, so you rarely get that heavy, stagnant feeling.
Tips for Visiting Cotonou in Summer
Summer in Cotonou means warm days, sticky air, and frequent rain showers. If you plan your outings with the weather in mind and pack the right clothes, you’ll have a much better time.
Best Times for Outdoor Activities
From June through September, rain is a regular guest, and June tends to get the most of it. Showers usually come in bursts, so mornings are your best bet for outdoor plans before afternoon storms roll in.
July and August feel a bit cooler. Average highs hover around 26–28 °C (79–82 °F), which makes walking tours or trips to the market a bit more pleasant. The sky’s cloudier, but honestly, that helps take the edge off the sun.
If you’re eyeing the beach, the sea stays warm—25.5 °C in August to 27 °C in July—so swimming’s on the table, though the water can get rough during storms.
Try to do your sightseeing, walking, or biking early in the day. Save indoor stops like museums or cultural centers for the afternoon when the rain and humidity usually peak.
What to Pack for the Weather
Bring light, breathable clothing—think cotton or linen. These fabrics help you deal with the heat and humidity. Toss in a light rain jacket or a compact umbrella, since those sudden, heavy showers love to show up uninvited.
You’ll want comfortable sandals or quick-drying shoes, especially for city streets that get wet after rain. Heading to the beach? Pack swimwear and water shoes so you don’t end up hopping across sharp rocks.
Don’t skip sun protection. I always grab a wide-brim hat, sunglasses, and sunscreen—UV rays don’t care if it’s cloudy.
For evenings, I suggest a light sweater or long-sleeve shirt. Coastal breezes can surprise you after sunset, even if the day felt warm.