Verdict: Fair month
Siem Reap Weather in September
September runs warm in Siem Reap, with daily highs around 31°C (88°F) and nights near 24°C (75°F). It's also the wet side of the calendar: rain falls on about 29 days, so build flexibility into plans. September is workable in Siem Reap if your dates are fixed — just plan around the conditions.
Average high
31°C / 88°F
Average low
24°C / 75°F
Rain days
~29
Precipitation
380 mm
What to pack for Siem Reap in September
- Light, breathable clothing — linen and technical fabrics earn their keep
- High-SPF sunscreen, sunglasses, and a refillable water bottle
- Rain gear is non-negotiable — expect rain on roughly 29 days
- Quick-dry shoes — downpours are short but heavy
- Comfortable walking shoes — every guide on this site assumes you'll use them
September against the rest of the year
Warmest in Siem Reap: Mar (35°C / 95°F) · Coolest: Oct (30°C / 86°F) · Wettest: Sep (~29 rain days)
31°
21°
Jan
33°
23°
Feb
35°
25°
Mar
34°
26°
Apr
33°
26°
May
33°
26°
Jun
32°
25°
Jul
32°
25°
Aug
31°
24°
Sep
30°
23°
Oct
30°
23°
Nov
30°
21°
Dec
Daily highs / lows in °C · bars show rain days per month · ERA5 climate normals (2020–2024)