Cambodia Siem Reap Weather in September — Climate Guide
September in Siem Reap is moderate
September is moderate for Siem Reap.
September is Siem Reap's wettest month — 18 rainy days, 275mm rainfall, 85% humidity. Daytime highs 32°C / 90°F (year's coolest). Some outer-temple roads (Beng Mealea, Koh Ker) become difficult to access.
Pchum Ben Festival (15-day Buddhist ancestor remembrance, with the public holiday usually late September or early October) brings atmospheric temple visits + food offerings + Khmer Buddhist culture experience.
Travel score
Wettest month + Pchum Ben Festival — quietest temples + lowest prices
September Weather at a Glance
September averages 32°C / 90°F highs and 24°C / 75°F lows with 18 rainy days and 275mm rainfall — the wettest month. Humidity 85%, UV 10. Sunrise 6:05 AM, sunset 5:55 PM. Daily thunderstorms can extend into evenings.
September Travel Advice
Outer temples (Beng Mealea, Koh Ker) check road conditions with driver. Pchum Ben Festival (date varies) brings atmospheric temple ceremonies. Tonle Sap at peak water — best floating-village photography of the year.
Flying In from Overseas
Monsoon-low — Western travelers minimal. Korean Chuseok holiday partial overlap brings modest inbound. Direct flights from Bangkok $30-80, Singapore $80-180.
September Pricing Trends
Annual low: Raffles $180-400/night, Park Hyatt $180-380, FCC Angkor $80-160, Onederz Hostel $8-18. Tuk-tuk $15-20/day.
Siem Reap September Weather Stats
Avg High
32°C
Avg Low
24°C
Rainy Days
18
275mm total
Sunshine
5h
Daily avg
Humidity
85%
high
UV Index
10
Very high
Wind
8 km/h
Gusts 25
Sea Temp
0°C
no swimming
Crowds
Quiet
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
22 μg/m³
PM10
38 μg/m³
Status
moderate
Feels-Like Temperature & Wind
Feels like
Daytime
36°C
Nighttime
26°C
Humidity and wind affect how the actual temperature feels.
Wind
8 km/h
Max gust 25 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- Annual low hotel pricing (50% off peak)
- Pchum Ben Festival cultural experience
- Tonle Sap at peak water level (all stilted villages visible)
Cons
- Wettest month (275mm rain)
- Outer-temple roads flood-risk
- Mosquito peak season
September Events & Festivals
- Wettest month of the year
- Pchum Ben Festival (Buddhist ancestor remembrance, late Sept-early Oct)
- Korean Chuseok approaches
Siem Reap in September — Full Picture
September is Siem Reap's wettest month — 18 rainy days, 275mm rainfall, 85% humidity. Daytime highs 32°C / 90°F (year's coolest). Some outer-temple roads (Beng Mealea, Koh Ker) become difficult to access.
Pchum Ben Festival (15-day Buddhist ancestor remembrance, with the public holiday usually late September or early October) brings atmospheric temple visits + food offerings + Khmer Buddhist culture experience.
Hotels hit annual low — 50% off peak. Raffles $180-400/night. Korean Chuseok holiday partial overlap brings modest Korean inbound bump.
For wet-weather photographers + cultural enthusiasts + budget travelers seeking the quietest temples, September is the canonical month.
What to Wear & What to Pack
Wettest month — quick-dry, rain jacket essential, waterproof shoes, insect repellent (mosquito peak season).
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
35.7°C
24.3°C
6.7/mo
Summer (Jun·Jul·Aug)
33.3°C
25°C
15/mo
Autumn (Sep·Oct·Nov)
Current31.7°C
23.3°C
13.7/mo
Winter (Dec·Jan·Feb)
32°C
21°C
1.3/mo
Siem Reap Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| January (Best) | 32° | 21° | 1d·10mm | 9h | 60% | 10 | Very busy | Peak |
| February (Best) | 33° | 21° | 1d·5mm | 10h | 55% | 10 | Very busy | Peak |
| March (Best) | 35° | 23° | 3d·25mm | 9h | 55% | 11 | Busy | Shoulder |
| 37° | 25° | 4d·50mm | 9h | 60% | 11 | Moderate | Shoulder | |
| 35° | 25° | 13d·175mm | 7h | 75% | 11 | Quiet | Low season | |
| 34° | 25° | 14d·175mm | 6h | 80% | 11 | Moderate | Low season | |
| 33° | 25° | 15d·200mm | 6h | 80% | 10 | Moderate | Shoulder | |
| 33° | 25° | 16d·225mm | 6h | 80% | 10 | Moderate | Shoulder | |
| 32° | 24° | 18d·275mm | 5h | 85% | 10 | Quiet | Low season | |
| 32° | 24° | 16d·230mm | 6h | 80% | 9 | Moderate | Low season | |
| November (Best) | 31° | 22° | 7d·70mm | 7h | 70% | 9 | Busy | Shoulder |
| December (Best) | 31° | 21° | 2d·15mm | 9h | 60% | 9 | Very busy | Peak |
View Other Months
Siem Reap September Hotel Picks
Frequently Asked Questions
Is September a good time to visit Siem Reap?
Siem Reap in September is moderate. Tourist crowds are quiet and flight/hotel prices are low season.
What's the average temperature in Siem Reap in September?
Siem Reap September averages a high of 32°C and a low of 24°C.
Does it rain much in Siem Reap in September?
Siem Reap September averages 275mm of rainfall over about 18 rainy days.
What should I wear in Siem Reap in September?
Wettest month — quick-dry, rain jacket essential, waterproof shoes, insect repellent (mosquito peak season).
What time are sunrise and sunset in Siem Reap in September?
Siem Reap September sunrise is 06:05 and sunset is 17:55, with 11h 50min of daylight.
What's the air quality like in Siem Reap in September?
Siem Reap September air quality (AQI) averages 60, rated Moderate. PM2.5 averages 22μg/m³.
What activities are recommended in Siem Reap in September?
In September, Siem Reap is great for Pchum Ben Festival temple visits, Pre-dawn Angkor, Tonle Sap peak water.
Is September peak season in Siem Reap?
Siem Reap September crowds are quiet and prices are low season. You can travel relatively comfortably without long queues.
Best Months to Visit Siem Reap
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.