February brings 31°C daytime highs, 7mm of precipitation across about 1 wet days and 11.6 hours of daylight — best for beach days and swimming. The strongest run of the year is January to March. September is the quietest month: wet but green, and still good for green season and quiet and local.
Long-run climate normals for Siem Reap. Month ratings compare months within Siem Reap only — they are not a ranking of Siem Reap against other destinations, and they are not a forecast for a specific year.
Last updated: · Live forecast data refreshes hourly.
| Best month | February — Beach days, Swimming |
| Best 3-month window | January–March |
| Quietest month | September — Wet but green |
| Driest month | January — 4mm |
| Wettest month | September — 235mm |
| Warmest / coolest | July 35°C / February 31°C |
| Seasonality | Strongly seasonal — the months feel like different places |
| Annual rainfall | 1365mm over roughly 102 rain days |
September gets roughly 3257% more precipitation than February — 235mm against 7mm. That difference, more than temperature, is what changes how a day here feels.
Daytime highs only move 4°C across the whole year (31–35°C), so timing matters far less here than rainfall does.
January is the driest month at 4mm across roughly 1 wet days, while September peaks at 235mm.
March is almost as good as February, but usually quieter and cheaper. If your dates are flexible, it is the easier trip.
Siem Reap changes character completely through the year — February and September are effectively two different destinations. Pick the month that matches what you want to do, not the highest-rated one.
Ratings compare months within Siem Reap, not against destinations worldwide: five stars means the best time to be here, not that Siem Reap beats anywhere else. Tags describe what the conditions actually suit.
| Month | Rating | High / Low | Precipitation | Wet days | Sun | Daylight | Best for |
|---|---|---|---|---|---|---|---|
| January | ★★★★★ | 31°C / 22°C | 4mm | 1 | 5h | 11.3h | Beach days · Swimming |
| February | ★★★★★ | 31°C / 22°C | 7mm | 1 | 8h | 11.6h | Beach days · Swimming |
| March | ★★★★★ | 32°C / 22°C | 30mm | 2 | 8h | 11.9h | Beach days · Swimming |
| April | ★★★★★ | 32°C / 23°C | 60mm | 5 | 9h | 12.3h | Beach days · Swimming · Reliable sunshine |
| May | ★★★☆☆ | 34°C / 24°C | 145mm | 11 | 6h | 12.6h | Beach days · Swimming |
| June | ★★☆☆☆ | 34°C / 25°C | 170mm | 13 | 5h | 12.8h | Beach days · Swimming · Quiet and local |
| July | ★★☆☆☆ | 35°C / 25°C | 195mm | 15 | 5h | 12.7h | Beach days · Swimming · Green season |
| August | ★★☆☆☆ | 35°C / 25°C | 210mm | 16 | 5h | 12.4h | Beach days · Swimming · Green season |
| September | ★★☆☆☆ | 34°C / 25°C | 235mm | 18 | 5h | 12.1h | Green season · Quiet and local |
| October | ★★☆☆☆ | 34°C / 24°C | 198mm | 15 | 4h | 11.7h | Beach days · Swimming · Green season |
| November | ★★★★☆ | 32°C / 23°C | 68mm | 5 | 4h | 11.4h | Beach days · Swimming |
| December | ★★★★★ | 32°C / 22°C | 15mm | 1 | 5h | 11.2h | Beach days · Swimming |
| You are planning | Pick | Why |
|---|---|---|
| Sun & beach days | February | 8h daily sunshine, 31°C highs and only 1 rain days. |
| City walking & sightseeing | January | 31°C highs with 11.3h of daylight — long days without heat fatigue. |
| Photography & light | February | 8h of sun and 11.6h daylight give the widest window for golden-hour work. |
| Value & fewer crowds | December | Scores 72/100 — close to peak conditions but outside the busiest window. |
| Cooler-weather travel | January | 31°C highs and 22°C nights suit anyone who dislikes heat. |
Each month in Siem Reap is described from long-run climate normals and then rated relative to the other eleven months in the same city. A five-star January in a cold destination means January is one of the best times to be there — not that it beats a Mediterranean summer.
| Factor | Weight | What it measures |
|---|---|---|
| Temperature | Described | Average daytime high and overnight low for the month, shown as measured rather than judged. |
| Precipitation | Described | Monthly millimetres and wet-day count, labelled as snow or rain/snow where temperatures make that the likely phase. |
| Sunshine & daylight | Described | Average daily sunshine hours and astronomical daylight length at mid-month, from the city’s latitude. |
| “Best for” tags | Derived | Applied only when the conditions genuinely support the activity — snow depth-friendly cold for skiing, 13–24°C and low rain risk for hiking, dark evenings at high latitude for aurora. A month with few strong use cases gets fewer tags rather than padded ones. |
| Star rating | Relative | Ranks the month against the other eleven months in the same city. Never a comparison between cities. |
Figures are long-run climate averages, not a forecast for a specific year. Where a month lacks sourced rainfall or humidity, the value is modelled from temperature range and rain frequency.
February is the best all-round month in Siem Reap: 31°C highs, 7mm of precipitation and 11.6 hours of daylight, which suits beach days and swimming. The strongest three-month window is January to March.
September — 34°C highs, 235mm of precipitation over roughly 18 days and 12.1 hours of daylight. It is the cheapest and least crowded time to go, and it still works for green season and quiet and local.
January is the driest month at 4mm over about 1 rain days, against 235mm in September. Across the year Siem Reap records around 1365mm.
Yes, but the months are genuinely different trips. February suits beach days and swimming, while September suits green season and quiet and local. Pick the month that matches what you want to do.
Daylight ranges from 11.2 hours in December to 12.8 hours in June, calculated from the city's latitude.