Monthly weather averages & travel planning

Asia › 🇻🇳 Vietnam › Hanoi
Updated: March 2026
August is a avoid time to visit Hanoi (3/10). With 8 daily sunshine hours and only 23 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 4th sunniest of the year in Hanoi. August suits travellers visiting for indoor culture, food, and architecture rather than outdoor activities. Pack accordingly for 23 potential rain days. September offers a similar profile at lower hotel rates if dates are flexible. Watch out for prolonged rain stretches: with 23 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.
The single most important thing to know about visiting Hanoi in August: rain is a genuine factor across 23 days of the month, meaning your plans need built-in indoor alternatives. Precipitation totals 320mm for the month, spread across roughly 23 days, and 8 sunshine hours per day give you a reliable window for outdoor plans.
31°C
88°F
Avg High
25°C
77°F
Avg Low
23 days
320 mm total
Rain Days
8h
per day avg
Sunshine
78%
Humid
Humidity
The 6°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 78% humidity, the 31°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 9 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Winds are calm at an average 11 km/h, so wind-chill is not a factor in planning your clothing. In Fahrenheit: 88°F average high, 77°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Packing for Hanoi in August means dressing for 31°C days and 25°C evenings. A lightweight linen or cotton shirt with loose-fit trousers or a sundress handles the 31°C daytime heat. Evening temperatures settle at 25°C, a modest 6°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 23 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 78% 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 Hanoi'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 Hanoi, 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 31°C average highs and 23 rainy days
Hanoi'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 31°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.
Hanoi in August
August ranks 4th sunniest of the year in Hanoi, with an average 8 daily sunshine hours. The driest months are November, December, and January. June is the hottest month (33°C avg high); January is the coolest (20°C). From here, temperatures fall 1°C into September. Compared to last month (July: 32°C high, 21 rain days), August is cooler and wetter. August sits in the middle of the annual sunshine ranking for Hanoi, offering a reasonable balance of good weather and manageable crowds.
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 20°C | 13°C | 8 | 4h | View |
| February | 22°C | 15°C | 8 | 4h | View |
| March | 25°C | 18°C | 11 | 4h | View |
| April | 29°C | 22°C | 11 | 7h | View |
| May | 31°C | 24°C | 17 | 8h | View |
| June | 33°C | 26°C | 19 | 8h | View |
| July | 32°C | 26°C | 21 | 8h | View |
| August | 31°C | 25°C | 23 | 8h | View |
| September | 30°C | 24°C | 19 | 8h | View |
| October | 28°C | 21°C | 12 | 8h | View |
| November | 25°C | 18°C | 7 | 7h | View |
| December | 21°C | 14°C | 7 | 6h | View |
January
8 rain days, 4h sun
February
8 rain days, 4h sun
March
11 rain days, 4h sun
April
11 rain days, 7h sun
May
17 rain days, 8h sun
June
19 rain days, 8h sun
July
21 rain days, 8h sun
August
23 rain days, 8h sun
September
19 rain days, 8h sun
October
12 rain days, 8h sun
November
7 rain days, 7h sun
December
7 rain days, 6h sun
Cities within 500 km with comparable weather conditions
Data Sources for Hanoi
Climate normals represent 30-year averages (1991-2020). Individual years may vary.