Monthly weather averages & travel planning

Asia › 🇰🇭 Cambodia › Phnom Penh
Updated: March 2026
August is a fair time to visit Phnom Penh (4/10). With 9 daily sunshine hours and only 25 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 10th sunniest of the year in Phnom Penh. August suits travellers visiting for indoor culture, food, and architecture rather than outdoor activities. Pack accordingly for 25 potential rain days. September offers a similar profile at lower hotel rates if dates are flexible. Watch out for prolonged rain stretches: with 25 wet days, a fully outdoor itinerary is risky. Build in museum days and covered market visits as contingency. Planning tips: most accommodation categories have availability, and last-minute deals are common. The quieter streets and shorter queues can make this a genuinely enjoyable time to visit for the right type of traveller. Budget-conscious visitors will find the best value of the year in this period.
Step off the plane in Phnom Penh in August and the air meets you at around 32°C, carrying the kind of warmth that makes you reach for sunglasses before your bag is off the belt. By the time evening arrives and temperatures settle near 25°C, the city takes on a different character entirely. With 9 hours of daylight sun on offer, August gives you the raw material for a genuinely memorable trip.
32°C
90°F
Avg High
25°C
77°F
Avg Low
25 days
179 mm total
Rain Days
9h
per day avg
Sunshine
82%
Humid
Humidity
The 7°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. At 82% humidity, the 32°C daytime high feels 2-4°C warmer in practice: quick-dry fabrics and shade-seeking between noon and 3pm are the sensible response. UV index averages 8 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Wind averages 15 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 90°F average high, 77°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Packing for Phnom Penh in August means dressing for 32°C days and 25°C evenings. A lightweight linen or cotton shirt with loose-fit trousers or a sundress handles the 32°C daytime heat. Evening temperatures settle at 25°C, a modest 7°C drop that a light cardigan or denim jacket covers. For footwear, breathable walking sandals work for casual exploration, but closed-toe trainers are better for uneven surfaces in the historic centre. With 25 rain days expected, a compact travel umbrella is worth the bag space. A waterproof jacket is better than an umbrella if you plan full-day outdoor routes. For temple and religious site visits, carry a lightweight scarf or sarong to cover shoulders and knees, required at most major sites across the region. At 82% average humidity, quick-dry synthetic or bamboo fabrics dry overnight and stay comfortable longer than cotton.
Local tip: Loose-weave linen and moisture-wicking fabrics are the practical choice in Phnom Penh's heat and humidity. Many shopping centres run air conditioning at near-arctic levels, so a thin layer in your bag prevents discomfort indoors.
August has no major festivals or public holidays in Phnom Penh, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
Based on 32°C average highs and 25 rainy days
Phnom Penh's August climate is governed by the Inter-Tropical Convergence Zone (ITCZ), which draws moisture-laden trade winds across the region, producing the characteristic wet season rainfall of steamy tropical cities. Daytime heat peaks around 32°C, moderated slightly by afternoon convective showers. Overnight temperatures remain warm at 25°C because the humid air retains heat effectively. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate, wear sunscreen. UV 6-7: High, hat and SPF 30+ essential. UV 8-10: Very High, limit midday exposure. UV 11+: Extreme, seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry, skin and throat may feel parched. 40-60%: Comfortable, ideal for most people. 60-80%: Sticky, light breathable fabrics recommended. Above 80%: Muggy, heat feels more intense; quick-dry clothing is essential.
Phnom Penh in August
August ranks 10th sunniest of the year in Phnom Penh, with an average 9 daily sunshine hours. The driest months are February, January, and December. March is the hottest month (35°C avg high); October is the coolest (30°C). From here, temperatures fall 1°C into September. Compared to last month (July: 32°C high, 25 rain days), August is similarly warm and equally dry. August is one of the least sunny months, but that often means lower prices and fewer fellow tourists.
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 32°C | 22°C | 3 | 11h | View |
| February | 33°C | 23°C | 2 | 11h | View |
| March | 35°C | 25°C | 6 | 11h | View |
| April | 35°C | 26°C | 14 | 11h | View |
| May | 34°C | 26°C | 23 | 11h | View |
| June | 32°C | 25°C | 24 | 10h | View |
| July | 32°C | 25°C | 25 | 9h | View |
| August | 32°C | 25°C | 25 | 9h | View |
| September | 31°C | 24°C | 27 | 9h | View |
| October | 30°C | 24°C | 25 | 9h | View |
| November | 30°C | 23°C | 11 | 10h | View |
| December | 31°C | 23°C | 5 | 10h | View |
January
3 rain days, 11h sun
February
2 rain days, 11h sun
March
6 rain days, 11h sun
April
14 rain days, 11h sun
May
23 rain days, 11h sun
June
24 rain days, 10h sun
July
25 rain days, 9h sun
August
25 rain days, 9h sun
September
27 rain days, 9h sun
October
25 rain days, 9h sun
November
11 rain days, 10h sun
December
5 rain days, 10h sun
Cities within 500 km with comparable weather conditions
Data Sources for Phnom Penh
Climate normals represent 30-year averages (1991-2020). Individual years may vary.