September · Cambodia
Best time to visit Phnom Penh in September Weather, crowds & prices
Weather in Phnom Penh in September
Average temperature 27°C, 375 mm of rain, about 25 days with 6+ hours of sunshine and 87% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
3.4/10
Ranked #10 of 12 months
- Avg temp
- 27°C
- Rainfall
- 375 mm
- Humidity
- 87%
- Days with 6h+ sun
- 25
- Crowd Density
- Quiet / Uncrowded
- Average Expenses
- $ · Budget Friendly ($)
September in Phnom Penh scores 3.4/10 for sightseeing and cultural travel - ranked #10 of 12. Expect around 27°C, 375 mm of rain, and roughly 25 days with 6+ hours of sunshine this month.
Phnom Penh pairs royal palaces and a riverfront with sobering museums of the Khmer Rouge years.
September in Phnom Penh: expect compromises
September averages 27°C (81°F) and humidity near 87%, so the practical pattern is early mornings, a long midday break, and evenings back outside.
375 mm makes this the wettest stretch of the year, though about 25 days with 6+ hours of sunshine still appear — keep an indoor fallback ready.
It scores 3.4/10 here, 10th of 12 months, against 8.1/10 in the destination's best month.
Pack the lightest breathable clothing you own, a hat, and more water than feels necessary, a proper rain shell rather than an umbrella.
Plan for low-season pricing, with crowds are light for this destination.
Flexible dates? January scores 4.7 points higher here — enough to change the trip.
Frequently asked
- What is the weather like in Phnom Penh in September?
- In September, Phnom Penh averages 27°C, 375 mm of rain, and about 25 days with 6+ hours of sunshine. Its climate-comfort score is 3.4/10.
- Is September a good time to visit Phnom Penh?
- September earns a 3.4/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Phnom Penh in September?
- Expect about 375 mm of rain in September. Average humidity is 87% and there are about 25 days with 6+ hours of sunshine.
Curated in Phnom Penh
Tickets & experiences
Things to do in Phnom Penh
Phnom Penh, Cambodia. Live activities and tours from GetYourGuide, matched to this destination.