If you’re planning a trip to Colombo in the summer, get ready for warm, sticky days and a sky that’s usually more gray than blue. Daytime highs usually reach about 87°F (30°C), and nights don’t cool down much—hovering around 80°F (27°C). You’ll notice the heat sticks around, and the temperature rarely swings much, so life in the city feels pretty consistent, whether you’re out in the afternoon or heading out after dark.
Clouds become a near-constant companion during these months. The sky often looks overcast or mostly cloudy. Rain showers pop up pretty often, especially at the start of summer, though they ease a bit later on. Humidity stays high, making the air feel heavy and sometimes a little uncomfortable if you’re not used to it.
Knowing what to expect makes planning easier. Whether you want to stroll along the coast, check out street markets, or just pack smart, understanding Colombo’s summer weather—temperature, rainfall, humidity, and wind—helps you have a better trip.
Overview of Colombo’s Summer Climate
Colombo gets hot and humid in summer, thanks to steady tropical temperatures and heavy monsoon rains. You’ll see plenty of cloud cover, high humidity, and rain that can make outdoor plans a bit trickier than in drier months.
Tropical Monsoon Characteristics
Colombo falls under the tropical monsoon climate, according to the Köppen system. So, you’ll get warm weather all year, but the amount of rain jumps up and down with the monsoon seasons.
In summer, daytime highs usually land in the 28–30°C (82–86°F) range. Nights stay warm too, often above 25°C (77°F). Humidity climbs over 80%, so the air feels damp and thick.
Rain really defines this time of year. June typically sees over 300 mm (12 in) of rain, making it one of the soggiest months. Most days bring some rain, often in quick, heavy bursts.
Clouds stick around, and sunshine hours drop to about 6–7 per day. That takes the edge off the heat a little, but it also means fewer clear days for sightseeing.
Seasonal Weather Patterns
Summer in Colombo lines up with the Southwest Monsoon. This system sweeps in from the Indian Ocean and dumps heavy rain from June through August.
Rainfall isn’t totally even. June is usually the wettest, July gets a little break, and then August picks up again. Still, temperatures don’t really budge from the high 20s Celsius.
Most days start out hot and sticky, then get a shower or two in the afternoon or evening. After a long downpour, low-lying areas sometimes flood.
Sunshine gets cut back compared to other seasons, averaging 6–7 hours daily. The sea also gets rougher, so swimming or boating might not be the safest bet.
Comparison to Other Sri Lankan Cities
Colombo’s summer feels hotter and stickier than places like Kandy or Nuwara Eliya inland. Being on the coast keeps temperatures steady, but the monsoon rains hit harder.
Kandy, up in the hills, gets less rain in summer and has cooler nights. Nuwara Eliya, sitting even higher, stays much cooler, with daytime highs closer to 20°C (68°F).
Over in Galle on the southern coast, rainfall totals look a lot like Colombo’s, just a bit less intense. If you’re chasing drier weather, the eastern coast near Trincomalee often stays sunnier at this time of year.
So, your experience really depends on where you go—even if you travel in the same month.
Average Summer Temperatures in Colombo
Colombo’s summer stays warm and steady, with barely any change from month to month. Daytime highs stick to the upper 80s °F, and nights stay warm, shaped by the city’s tropical monsoon setup.
Daytime and Nighttime Temperature Ranges
In summer, daytime highs in Colombo hover around 86–87°F (30–31°C). It’s rare for temperatures to dip below 84°F or climb above 90°F, so the heat doesn’t really swing much.
At night, average lows sit near 79–80°F (26–27°C). Even after sunset, it feels warm and humid, which is pretty typical for a coastal city. Nights almost never drop below 76°F, so don’t expect much cooling off.
This tight range between day and night temps gives the city a pretty even feel. The nearby ocean helps keep things from getting too extreme.
Monthly Temperature Variations
Monthly averages in summer barely move. June, July, and August all see highs near 87°F and lows around 80°F. Unlike places with big seasonal swings, Colombo’s tropical climate keeps changes small.
Here’s a quick look at the monthly averages:
| Month | Avg High °F (°C) | Avg Low °F (°C) |
|---|---|---|
| June | 87 (31) | 80 (27) |
| July | 86 (30) | 79 (26) |
| August | 87 (31) | 79 (26) |
This means you can plan your trip without stressing over big temperature changes from one summer month to another.
Hottest and Coolest Summer Months
Colombo’s hottest stretch usually hits in April, right before summer officially starts. By the time summer rolls around, the heat eases just a bit, but highs stay steady around 86–87°F.
Within summer, June and August feel a touch warmer than July, though it’s only by about 1°F. July tends to be the coolest, with average highs near 86°F.
Even in the “coolest” summer month, Colombo stays hot and humid. You won’t run into any real cool spells, and the difference between the hottest and coolest months is pretty minor. That makes the weather easy to predict and pack for.
Summer Precipitation and Rainfall Trends
Colombo’s summer brings a mix of steady rain and high humidity, all thanks to the southwest monsoon. You’ll get frequent showers, heavy downpours, and the occasional sunny break—so conditions stay variable, but not really surprising.
Monthly Rainfall Amounts
The southwest monsoon drives summer rainfall in Colombo. From May through September, rain totals stay high compared to the rest of the year.
- May: ~370 mm
- June: ~240 mm
- July: ~120 mm
- August: ~120 mm
- September: ~240 mm
May brings the heaviest rain of the year. June and September also get a lot, while July and August are a bit drier but still see plenty of showers.
Even the “drier” summer months get more rain than many places worldwide. If you’re planning to spend a lot of time outside, bring rain gear and expect wet weather.
Number of Rainy Days
Rain in Colombo during summer spreads out over many days, not just a few storms. On average, you’ll see 12 to 18 rainy days a month.
- May: ~16 days
- June: ~14 days
- July: ~12 days
- August: ~12 days
- September: ~15 days
Showers usually come in quick, heavy bursts, most often in the afternoon or evening. Mornings are often dry and better for sightseeing or getting around.
Even in months with fewer rainy days, humidity stays high and clouds are common. It’s smart to keep your plans flexible—sudden showers are just part of life here.
Monsoon Influence on Rainfall
The southwest monsoon brings most of Colombo’s summer rain. Moist air from the Indian Ocean moves inland, causing heavy showers and thunderstorms.
This monsoon pattern explains why May and September get so much rain—they mark the start and end of the season. July and August see a bit less rain, but it’s still a lot compared to most places.
Because of the monsoon, daily weather can shift. Some days bring hours of rain, others just a quick downpour. This rhythm really shapes what summer feels like in Colombo.
Humidity and Comfort Levels During Summer
Colombo’s summer combines high temperatures with humidity that barely lets up. This combo changes how hot it feels and affects your energy, comfort, and how much time you want to spend outside.
Average Humidity by Month
In summer, humidity in Colombo usually sits between 70% and 80%. The southwest monsoon, running from May through September, pushes it toward the higher end.
June often tops out around 79% humidity, making it one of the muggiest months. February is the least humid, averaging about 69%, but that’s outside summer.
Here’s a quick breakdown:
| Month | Average Humidity | Conditions |
|---|---|---|
| May | ~75% | Start of monsoon, rising humidity |
| June | ~79% | Peak humidity, frequent rain |
| July | ~77% | Humid with steady showers |
| August | ~76% | Slightly lower but still high |
| September | ~75% | Humid, with lingering monsoon effects |
At these levels, even 30–32°C feels hotter because all that moisture slows down how fast your body cools off.
Impact on Daily Life and Activities
High humidity changes how you tackle your day in Colombo. Walking tours or market visits can feel exhausting, especially in the afternoon when the heat and humidity peak.
You’ll probably find mornings and evenings more comfortable for getting out and about. If you need a break, indoor spots with fans or AC offer real relief, especially in June and July when the air feels thickest.
What you wear matters. Light, breathable fabrics like cotton help you stay cooler. Carry water—sweating doesn’t cool you off as much when it’s humid.
If you’re heading to the beach or a pool, the sea breeze can help. But inland, where air doesn’t move much, it can get uncomfortable fast. Adjusting your plans makes the weather easier to handle.
Additional Summer Weather Factors
When you plan for summer in Colombo, you need to think about more than just temperature and rain. Sunshine, wind, and sea conditions all play a part in how your days actually feel.
Sunshine Hours and Cloud Cover
Colombo’s tropical monsoon climate means clear skies are rare in summer. The city averages 6 to 8 hours of sunshine per day, but cloud cover stays high. Skies are overcast or mostly cloudy more than 80% of the time during peak summer months.
This mix of sun and cloud changes how hot it feels. Direct sun can feel intense, but clouds often give you a break from the heat. Still, humidity lingers, so even gray days feel muggy.
If you’re planning outdoor activities, try to go early in the morning or later in the evening. Midday can feel rough, with both heat and glare—even if the sky looks cloudy.
Wind Patterns and Breezes
Winds in Colombo stay light to moderate in summer, usually around 1 to 2 meters per second. These breezes offer some relief from the humidity but don’t really change the weather.
The southwest monsoon brings slightly stronger winds in June through August. You’ll notice this more along the coast, where shade plus a breeze can actually feel pretty nice.
Since wind speeds are low, the city sometimes feels stuffy, especially in the late afternoon. If you’re near the beach, though, the sea breeze can make a real difference compared to being further inland.
Sea Water Temperatures
Sea water around Colombo stays warm all summer, usually hovering between 27°C and 28°C (81°F to 82°F). You’ll find swimming and other water activities pretty comfortable the whole season.
The Indian Ocean keeps things cozy, so you won’t need wetsuits or any special gear for casual swims. Even if you dip in early in the morning or after sunset, the water still feels pleasant.
Humidity runs high, and the warm water can make the air along the coast feel a bit heavy, especially when the wind dies down. Still, you can count on stable sea temperatures in Colombo’s summer, which is great if you’re after both relaxation and fun.
Travel Tips for Experiencing Colombo’s Summer
Colombo’s summer brings warm days, plenty of humidity, and lots of clouds. As the season goes on, rain usually lets up, so outdoor activities get easier later in the summer. Planning ahead helps you enjoy the city’s cultural spots, beaches, and events without feeling too uncomfortable.
Best Time to Visit
Think about both the weather and your own comfort when you plan a summer trip. Early summer tends to get more rain, but July and August usually mean fewer showers and evenings that feel a bit cooler. Daytime highs stick around 86–88°F (30–31°C), while nights don’t drop much below 80°F (27°C).
Humidity stays up there, so expect muggy days and nights. If you’d rather avoid rain, late July into August is usually your best bet. Skies clear up a bit compared to June, though you’ll still see plenty of clouds.
If you want to sightsee, mornings are the best time to get out and explore. Afternoons can feel stifling, especially if you’re outdoors. Evenings work better for a stroll along Galle Face Green or checking out local markets when the heat finally lets up a little.
Packing Recommendations
Pack light, breathable clothes that can handle the heat and humidity. Cotton and linen are your friends here. A light rain jacket or a small umbrella comes in handy, especially in June when showers still pop up.
You’ll want comfortable walking shoes for getting around Colombo’s busy streets and the coast. Sandals work for casual days, but closed shoes are better if it’s wet. Don’t forget a hat, sunglasses, and sunscreen—the sun can be strong, even if it’s cloudy.
Since humidity is no joke, quick-dry clothing keeps things comfortable. Carry a reusable water bottle so you can stay hydrated. If you’re planning to visit temples, make sure to pack modest clothes that cover your shoulders and knees. A light scarf or shawl is useful for those visits too.
Popular Activities and Events
Colombo gives you a mix of cultural, coastal, and city experiences in the summer. Maybe you’ll wander along Galle Face Green for a breezy beachfront walk, or check out the Colombo National Museum if you’re into history.
You could always take a quick ride out to Mount Lavinia Beach. It’s close enough for a spontaneous trip if you want a break from the city.
Pettah’s markets let you dig into spices, textiles, and local snacks. I’d recommend checking out the evening food stalls on Marine Drive—people love grabbing Sri Lankan street food there, and honestly, it’s hard to resist the smells.
If you’re lucky and your trip lines up with a festival, you might catch a burst of color with parades, temple ceremonies, or traditional performances. These events can get crowded, so you’ll probably want to give yourself extra time to get around.
Most folks find outdoor activities more comfortable in the mornings or evenings, when the heat isn’t quite so relentless.