January brings 32°C daytime highs, 21mm of precipitation across about 2 wet days and 11.4 hours of daylight — best for beach days, swimming and reliable sunshine. The strongest run of the year is December to February. August is the quietest month: hot and slow-paced, and still good for beach days, swimming and green season.
Long-run climate normals for Phnom Penh. Month ratings compare months within Phnom Penh only — they are not a ranking of Phnom Penh against other destinations, and they are not a forecast for a specific year.
Last updated: · Live forecast data refreshes hourly.
| Best month | January — Beach days, Swimming, Reliable sunshine |
| Best 3-month window | December–February |
| Quietest month | August — Hot and slow-paced |
| Driest month | January — 21mm |
| Wettest month | September — 129mm |
| Warmest / coolest | June 35°C / December 32°C |
| Seasonality | Strongly seasonal — the months feel like different places |
| Annual rainfall | 900mm over roughly 96 rain days |
August gets roughly 514% more precipitation than January — 129mm against 21mm. That difference, more than temperature, is what changes how a day here feels.
Daytime highs only move 3°C across the whole year (32–35°C), so timing matters far less here than rainfall does.
January is the driest month at 21mm across roughly 2 wet days, while September peaks at 129mm.
February is almost as good as January, but usually quieter and cheaper. If your dates are flexible, it is the easier trip.
Phnom Penh changes character completely through the year — January and August are effectively two different destinations. Pick the month that matches what you want to do, not the highest-rated one.
Ratings compare months within Phnom Penh, not against destinations worldwide: five stars means the best time to be here, not that Phnom Penh beats anywhere else. Tags describe what the conditions actually suit.
| Month | Rating | High / Low | Precipitation | Wet days | Sun | Daylight | Best for |
|---|---|---|---|---|---|---|---|
| January | ★★★★★ | 32°C / 22°C | 21mm | 2 | 12h | 11.4h | Beach days · Swimming · Reliable sunshine |
| February | ★★★★★ | 32°C / 22°C | 21mm | 2 | 12h | 11.6h | Beach days · Swimming · Reliable sunshine |
| March | ★★★★★ | 33°C / 23°C | 39mm | 4 | 11h | 11.9h | Beach days · Swimming · Reliable sunshine |
| April | ★★★★☆ | 34°C / 24°C | 57mm | 6 | 10h | 12.3h | Beach days · Swimming · Reliable sunshine |
| May | ★★★☆☆ | 34°C / 25°C | 75mm | 8 | 9h | 12.5h | Beach days · Swimming · Reliable sunshine |
| June | ★★★☆☆ | 35°C / 26°C | 93mm | 10 | 8h | 12.7h | Beach days · Swimming · Quiet and local |
| July | ★★☆☆☆ | 35°C / 26°C | 111mm | 12 | 7h | 12.6h | Beach days · Swimming · Quiet and local |
| August | ★★☆☆☆ | 35°C / 26°C | 129mm | 14 | 6h | 12.4h | Beach days · Swimming · Green season |
| September | ★★☆☆☆ | 34°C / 25°C | 129mm | 14 | 6h | 12.1h | Beach days · Swimming · Green season |
| October | ★★☆☆☆ | 34°C / 24°C | 111mm | 12 | 7h | 11.7h | Beach days · Swimming · Quiet and local |
| November | ★★★★☆ | 33°C / 23°C | 75mm | 8 | 9h | 11.5h | Beach days · Swimming · Reliable sunshine |
| December | ★★★★★ | 32°C / 22°C | 39mm | 4 | 11h | 11.3h | Beach days · Swimming · Reliable sunshine |
| You are planning | Pick | Why |
|---|---|---|
| Sun & beach days | January | 12h daily sunshine, 32°C highs and only 2 rain days. |
| City walking & sightseeing | January | 32°C highs with 11.4h of daylight — long days without heat fatigue. |
| Photography & light | February | 12h of sun and 11.6h daylight give the widest window for golden-hour work. |
| Value & fewer crowds | March | Scores 73/100 — close to peak conditions but outside the busiest window. |
| Cooler-weather travel | January | 32°C highs and 22°C nights suit anyone who dislikes heat. |
Each month in Phnom Penh 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.
January is the best all-round month in Phnom Penh: 32°C highs, 21mm of precipitation and 11.4 hours of daylight, which suits beach days, swimming and reliable sunshine. The strongest three-month window is December to February.
August — 35°C highs, 129mm of precipitation over roughly 14 days and 12.4 hours of daylight. It is the cheapest and least crowded time to go, and it still works for beach days, swimming and green season.
January is the driest month at 21mm over about 2 rain days, against 129mm in September. Across the year Phnom Penh records around 900mm.
Yes, but the months are genuinely different trips. January suits beach days, swimming and reliable sunshine, while August suits beach days, swimming and green season. Pick the month that matches what you want to do.
Daylight ranges from 11.3 hours in December to 12.7 hours in June, calculated from the city's latitude.