Weather in Hanoi in August

A hard month. August is a hard month in Hanoi, and worth planning around. You should expect rain on 24 days of the month, which is more days wet than dry.

August ranks 10 of 12 — near the bottom of Hanoi's year. December is the month that works, and the swing between the two is 57 points, which is a different holiday rather than a slightly better one.

Rain on 24 of the month's 31 days, 10 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Natural fibres and a second shirt for the day. At 86% nothing dries, including you.

What the averages hide

Averages flatten a month, and this one hides a few things: 27 days top 30 °C, making the heat continuous rather than occasional. Across the twenty years measured, the hottest August day reached 36.1 °C and the coldest night fell to 22 °C, and the wettest single day dropped 99 mm — roughly 31% of the month's rain in one day.

August is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest August on record still delivered 472 mm against 168 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 322 mm average is a reasonable planning figure, not a promise.

Wind is light at 4.9 km/h, so the temperature on the page is close to the temperature on your skin, and humidity at 86% is the real story though — it is the number that decides how the day feels, not the 31.8 °C.

How August sits in the year

Temperatures hold steady either side: 32.5 °C in July, 31.8 here, 31 in September. Nothing about the timing within the month matters much. Rain is the thing that moves: September brings 6 days less of it, so pushing the dates later buys drier weather.

Daylight in August

August is at or near the longest days of Hanoi's year: 12.9 hours of daylight, losing 0.5 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

An inland climate

Despite being inland, the year stays fairly even: 21.2 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

August in Hanoi versus nearby

If Hanoi is one option among several, the nearby comparison is worth making. Haiphong is close enough to be a coin toss — within a degree on temperature, 2 days more rain. Thanh Hóa is close enough to be a coin toss — within a degree on temperature, 1 day less rain.

So: August is a compromise. December is 54 points better and is what Hanoi is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Hanoi

See all twelve months in Hanoi, or where else to go in August.