Weather in Hanoi in May

A hard month. May is a hard month in Hanoi, and worth planning around. You should expect rain on 18 days of the month, which is more days wet than dry.

May ranks 9 of 12 in Hanoi: past the worst of the year but short of December, which is the month to book if the dates are open.

Rain on 18 days, 6 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 32.7 °C days and 24.2 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 7 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest May day reached 42.2 °C and the coldest night fell to 17.8 °C, and the wettest single day dropped 61 mm — roughly 34% of the month's rain in one day.

May is one of the reliable ones — rainfall has stayed between 117 mm and 292 mm across all twenty years, a narrow enough band that the 179 mm average is something you can plan against rather than merely quote.

Wind is light at 6.7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 80%, high enough to notice on the warm days without dominating them.

How May sits in the year

Temperatures hold steady either side: 31.5 °C in April, 32.7 here, 32.8 in June. Nothing about the timing within the month matters much. Rain has already shifted: 6 days more than April had.

Daylight in May

May is at or near the longest days of Hanoi's year: 13.1 hours of daylight, gaining 0.4 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

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

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

May 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, the same number of rain days. Thanh Hóa is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: May is a compromise. December is 53 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 May.