Thinking about a summer trip to São Tomé? You’ll get warm, steady tropical weather, thanks to its spot near the Equator. Daytime temperatures usually hover around 27–30 °C (81–86 °F), with nights only a little cooler.
The air can feel humid, but breezes from the Gulf of Guinea often take the edge off.
Rainfall drops sharply in the middle of the year, so summer brings some of the driest weather you’ll find here. Clouds often linger overhead, but long stretches of sunshine still break through, so you’ll have plenty of time to hit the coast or wander the island’s green hills.
This mix of warmth, lighter rain, and manageable humidity makes summer a reliable season for outdoor fun. Whether you’re swimming in calm seas, hiking misty hills, or just relaxing on quiet beaches, the summer climate sets a pretty steady stage for your plans.
Overview of Summer Climate in Sao Tome
Summer in São Tomé means steady warmth, high humidity, and a noticeable drop in rain compared to other times of year. The island’s spot near the equator shapes its climate, while ocean currents and trade winds help keep temperatures in check.
Geographical Influence on Weather
São Tomé sits in the Gulf of Guinea, just above the equator. This location gives the island a tropical rainforest climate with hardly any temperature swings year-round.
Elevation matters too. The interior highlands feel cooler and wetter than the coast.
The Atlantic Ocean really shapes daily weather. Sea temperatures stay warm, usually about 26–28 °C (79–82 °F), which keeps the air humid and brings frequent clouds.
Trade winds from the southwest usually bring moisture, but in summer, these winds weaken, so things get drier. That’s why rainfall drops so much in June and July compared to the wet season earlier on.
Since São Tomé is a small island, weather can switch up fast. You might see clear skies by the coast, while the mountains stay misty.
Typical Summer Climate Patterns
From June to August, daytime temperatures in São Tomé average 27–28 °C (81–82 °F). Nights are mild too, usually not dipping below 22–23 °C (72–73 °F).
Humidity sticks around, often above 80%, but with less rain, the air feels less stuffy than in the wetter months.
Rainfall bottoms out in summer. June might see about 15–20 mm of rain, and July often gets almost none. August stays pretty dry, though a quick shower can still surprise you.
Sunshine hours go up during this time. You’ll get around 5–6 hours of sun per day, which is more than in cloudier months like March or October.
Winds stay light, and storms don’t show up much. The calm seas make it a good season for swimming, diving, and boat trips around São Tomé & PrÃncipe.
Average Temperatures During Summer
In São Tomé, summer brings steady warmth with only small changes between day and night. The season features mild highs, cooler evenings, and less rain than other parts of the year.
Daytime and Nighttime Temperature Ranges
During summer, daytime highs in São Tomé usually land between 25.5°C and 27°C (78°F–81°F). The heat isn’t extreme, and the ocean breeze helps keep things comfortable.
At night, temperatures drop just a bit, often settling around 23°C to 24°C (73°F–75°F).
This narrow range means you can plan both daytime and evening activities without worrying about big temperature swings. Light clothing works well, but you might want a thin layer at night.
Monthly Temperature Variations
Summer in São Tomé runs from June through September. June is usually the warmest, with highs near 26.7°C (80°F). By July and August, highs dip a little to 26°C (79°F), and nights cool to about 24°C (75°F).
September keeps things similar, so it’s one of the most balanced months for travel.
Here’s a quick look at the averages:
| Month | Day High (°C/°F) | Night Low (°C/°F) |
|---|---|---|
| June | 26.7 / 80 | 24 / 75 |
| July | 26 / 79 | 24 / 75 |
| August | 26 / 79 | 23.5 / 74 |
| September | 26.5 / 80 | 24 / 75 |
Comparison With Other Seasons
Wet seasons in March–May and October–December bring slightly hotter, more humid weather. Highs can reach 29°C to 30°C (84°F–86°F), and the humidity makes it feel even warmer.
In summer, you get moderate highs and lighter rainfall, so it’s more comfortable. Evenings are less humid, so walking along the coast or eating outside feels easier.
The variation isn’t huge, but summer offers the mildest stretch of the year. This balance of warmth and lower humidity makes it one of the best times to be outside without feeling sticky or overheated.
Rainfall and Precipitation Trends
Rainfall in São Tomé follows a clear rhythm, with wet months bringing heavy downpours and dry months offering a break. Both the amount of rain and the number of rainy days shift as the year goes on.
Monthly Rainfall Totals
Rain in São Tomé doesn’t spread out evenly over the year. The island averages about 1,400 mm of precipitation annually, but monthly totals swing a lot.
The wettest period usually comes in October and November, when monthly rainfall can top 200 mm. In July, you often see less than 20 mm, making it the driest time of year.
| Month | Average Rainfall (mm) |
|---|---|
| May | ~150 |
| June | ~20 |
| July | ~18 |
| October | ~200+ |
| November | ~220+ |
These numbers show a tropical climate where heavy showers rule the wet season, while the dry season brings only light, scattered rain.
Rainy Days Frequency
The number of rainy days matters too. In November, you might see about 17 rainy days, so showers show up more than half the month.
In the driest months like July, rain is rare, with only 6–7 days seeing any measurable precipitation.
So, even in the dry season, a quick shower can happen, but it’s usually brief and doesn’t cause much trouble.
Transition Between Dry and Wet Periods
The shift between dry and wet seasons in São Tomé happens gradually, not all at once. Rain starts to fade in May and June, kicking off the drier stretch.
From August into September, you’ll notice moisture creeping back, leading into heavier rains in October and November. Some weeks feel dry, others get hit by sudden heavy showers.
Travelers might find these in-between months appealing. They bring a mix of sunshine and rain, so you can plan outdoor activities and still see the island’s lush, green landscapes.
Sunshine Hours and Cloud Cover
In São Tomé, summer days bring a mix of steady clouds and moderate sunshine. You won’t get endless blue skies like some tropical places, but daylight hours stay pretty consistent.
Average Daily Sunshine Hours
During summer, you’ll get about 5 to 6 hours of sunshine each day. June averages closer to 5.5 hours, while July and August stick to a similar range.
That’s less than some other equatorial islands, but daylight itself holds steady at about 12 hours.
It’s worth noting the difference between daylight and sunshine hours. The sun rises early and sets at about the same time daily, but cloud cover means you won’t always see direct sunlight.
On average, São Tomé gets about 1,700 hours of sunshine per year, which is less than some sunnier equatorial spots. For summer visitors, it’s smart to expect a mix of bright spells and cloudy skies.
Light clothes are good, but you’ll want something for shade and humidity too.
| Month | Avg. Sunshine Hours (per day) |
|---|---|
| June | ~5.5 hours |
| July | ~5.0–5.5 hours |
| August | ~5.0 hours |
Cloudiness Patterns in Summer
Cloud cover really shapes São Tomé’s summer. About two-thirds of the time (around 68%), the sky stays overcast or mostly cloudy.
You’ll get a soft, filtered light most days. The clearest stretch usually pops up in late June, around June 29, when skies are clearer up to 36% of the time.
July and August bring back more clouds, but rain stays rare. Most summer days see little to no measurable precipitation.
Clouds help cut down on glare and heat, so outdoor conditions feel warm but not harsh.
Plan for steady brightness rather than long, direct sun. It’s comfortable for sightseeing, though maybe not ideal for sunbathing all day.
Humidity and Wind Conditions
During summer in São Tomé, you’ll notice less rain, which changes both humidity and wind. The air feels lighter than in the wet season, and coastal breezes offer relief from the heat.
Average Humidity Levels
Humidity in June, July, and August usually sits between 77% and 79%. That’s lower than the peak rainy season, when it can hit 83–85%.
You’ll still feel moisture in the air, but the drop makes outdoor activities more pleasant. Evenings cool off, with lows near 20–21°C (68–70°F), balancing out the daytime warmth.
Lower humidity means a bit less cloud cover than in wetter months. Sunshine hours climb to about 5 hours a day, so you get clearer skies for sightseeing or beach time.
The air stays tropical, but the reduced dampness makes these months some of the nicest for travel.
Prevailing Winds and Speeds
Winds in São Tomé during summer blow mostly from the southwest, shaped by the Atlantic trade winds. These breezes are steady but gentle, averaging 8–15 km/h (5–9 mph).
You’ll feel slightly stronger gusts along the coast, especially in the afternoons. Inland, hills and forests calm things down.
Gentle winds help keep the heat in check and stop the air from getting too still. They also create mild sea conditions, so boat trips and fishing are more reliable now.
For travelers, the combo of lighter humidity and steady breezes makes summer a really comfortable time to explore São Tomé’s outdoors.
Best Time to Visit Sao Tome in Summer
The middle of the year brings São Tomé’s driest, most comfortable weather. Rainfall drops to its lowest, humidity eases up, and temperatures stay warm without getting too hot, making it a great stretch for exploring both the coast and inland spots.
Optimal Months for Outdoor Activities
From June to August, São Tomé gets its driest weather of the year. Rain barely falls—June brings just about 19 mm, and July? Sometimes it barely rains at all.
Trails, beaches, and rural roads open up since the mud dries out. Honestly, it’s just easier to get around.
Daytime highs usually sit between 27°C and 28°C (81°F–82°F). Nights feel cooler, dropping to around 20°C–21°C (68°F–70°F).
Humidity drops to about 77–79%, so hiking or wandering the city feels less sticky. You might even forget you’re in the tropics for a moment.
These months stand out for a few reasons:
- Hiking in Obo National Park
- Snorkeling and diving with clearer underwater visibility
- Birdwatching in drier forest areas
- Exploring plantations without heavy afternoon showers
If you want to mix both land and sea adventures without worrying about the weather, this is probably your best bet.
Weather Considerations for Travelers
Summer in São Tomé brings steady temperatures, but travelers still need to prepare for those classic tropical vibes. The UV index gets pretty high, so honestly, sun protection is a must—even if it looks cloudy out. Pack some lightweight clothes, toss in a hat, and don’t forget reef-safe sunscreen.
Sea temperatures hover between 25°C and 26°C (77°F–79°F), so swimming feels great all season. Winds tend to stay light, so if you’re thinking about a boat trip to the islets, it’s usually smooth sailing.
Humidity drops compared to other months, though you might notice it creeping in around midday. Try to plan strenuous activities for early morning or later in the afternoon.
Always carry water, since shade can be weirdly hard to find on some of the coastal trails.