Sri Lanka Colombo Weather in September — Climate Guide
September in Colombo is moderate
September is moderate for Colombo.
September is the tail of the southwest monsoon in Colombo, with showers increasing again toward the end of the month as the second inter-monsoon approaches. It averages a warm, humid 30°C/25°C with about 160mm of rain.
It's a low-season month — sights are quiet and hotel prices soft — though the weather on the west and south coasts is still mixed. Early September can offer decent windows; the latter half trends wetter.
Travel score
Colombo September Weather Stats
Avg High
30°C
Avg Low
25°C
Rainy Days
12
160mm total
Sunshine
7h
Daily avg
Humidity
78%
muggy
UV Index
11
Extreme
Wind
12 km/h
Gusts 24
Crowds
Quiet
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
19 μg/m³
PM10
36 μg/m³
Status
good
Feels-Like Temperature & Wind
Feels like
Daytime
36°C
Nighttime
27°C
Humidity and wind affect how the actual temperature feels.
Wind
12 km/h
Max gust 24 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- Low-season prices and quiet sights
- Workable weather windows early in the month
- Good for indoor-focused city touring
- Fewer crowds at temples and museums
Cons
- Rain picks back up late in the month
- West/south beaches still unreliable
- East-coast dry season ending
- High humidity
September Events & Festivals
- Tail of the southwest monsoon
- Binara Poya (September full moon)
- Low season — quiet sights and soft prices
- Transition toward the October inter-monsoon
Colombo in September — Full Picture
September is the tail of the southwest monsoon in Colombo, with showers increasing again toward the end of the month as the second inter-monsoon approaches. It averages a warm, humid 30°C/25°C with about 160mm of rain.
It's a low-season month — sights are quiet and hotel prices soft — though the weather on the west and south coasts is still mixed. Early September can offer decent windows; the latter half trends wetter.
The east coast's dry season is ending around now, so the timing for beaches across the island gets trickier.
Note: this is a value month for the city if you don't mind some rain and plan flexible, indoor-friendly options (Gangaramaya, the National Museum, the Old Dutch Hospital). Keep an umbrella handy and watch the forecast before committing to coastal day trips.
What to Wear & What to Pack
Tail of the southwest monsoon — warm and humid around 30°C/25°C with showers picking back up toward month's end. Light quick-dry clothing, an umbrella, SPF 50+. A sarong for temples.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
31.7°C
25°C
13/mo
Summer (Jun·Jul·Aug)
30°C
26°C
12/mo
Autumn (Sep·Oct·Nov)
Current30°C
24.3°C
16/mo
Winter (Dec·Jan·Feb)
30.7°C
23°C
8.3/mo
Colombo Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| January (Best) | 31° | 23° | 8d·60mm | 8h | 75% | 11 | Busy | Peak |
| February (Best) | 31° | 23° | 6d·70mm | 9h | 73% | 12 | Busy | Peak |
| March (Best) | 32° | 24° | 8d·110mm | 8.5h | 75% | 12 | Busy | Shoulder |
| 32° | 25° | 14d·230mm | 7.5h | 78% | 12 | Moderate | Shoulder | |
| 31° | 26° | 17d·350mm | 6.5h | 80% | 11 | Quiet | Low season | |
| 30° | 26° | 15d·220mm | 6.5h | 79% | 11 | Quiet | Low season | |
| 30° | 26° | 11d·135mm | 7h | 78% | 11 | Moderate | Shoulder | |
| 30° | 26° | 10d·110mm | 7.5h | 77% | 11 | Moderate | Shoulder | |
| 30° | 25° | 12d·160mm | 7h | 78% | 11 | Quiet | Low season | |
| 30° | 24° | 19d·350mm | 6h | 80% | 11 | Quiet | Low season | |
| 30° | 24° | 17d·320mm | 6.5h | 80% | 11 | Moderate | Shoulder | |
| December (Best) | 30° | 23° | 11d·150mm | 7.5h | 77% | 11 | Busy | Peak |
View Other Months
Colombo September Hotel Picks
Frequently Asked Questions
Is September a good time to visit Colombo?
Colombo in September is moderate. Tourist crowds are quiet and flight/hotel prices are low season.
What's the average temperature in Colombo in September?
Colombo September averages a high of 30°C and a low of 25°C.
Does it rain much in Colombo in September?
Colombo September averages 160mm of rainfall over about 12 rainy days.
What should I wear in Colombo in September?
Tail of the southwest monsoon — warm and humid around 30°C/25°C with showers picking back up toward month's end. Light quick-dry clothing, an umbrella, SPF 50+. A sarong for temples.
What time are sunrise and sunset in Colombo in September?
Colombo September sunrise is 06:00 and sunset is 18:10, with 12h 10min of daylight.
What's the air quality like in Colombo in September?
Colombo September air quality (AQI) averages 46, rated Good. PM2.5 averages 19μg/m³.
What activities are recommended in Colombo in September?
In September, Colombo is great for Indoor city temples and the National Museum, Old Dutch Hospital dining, Quiet low-season sightseeing.
Is September peak season in Colombo?
Colombo September crowds are quiet and prices are low season. You can travel relatively comfortably without long queues.
Best Months to Visit Colombo
View Other Months
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.