Hanoi hava durumu: ay ay

January here is not cold by the numbers and is cold to be in. Regulars describe grey, overcast, damp weeks with a drizzle so fine it barely wets your clothes, and the line worth carrying is that 15C feels nearer 10C because of the humidity - our row reads 20.8C by day and 15.4C at night at 77 percent, with only 4.2 hours of sun a day, the least of this city's year. Rain totals 57.5mm across 9.6 days, almost all of it that drizzle. Pack layers rather than a coat. Tet moves with the lunar calendar and often falls in late January, when the city empties and much of it closes - check the year. The record: AQI 111.

February in the north is cold by Vietnamese standards and grey rather than wet: regulars describe light drizzle and mist growing more frequent through the month, persistent but so fine it does not dampen clothing. Our row carries the proof in an unusual column - 4.2 hours of sun a day, the lowest in this collection, against only 42.1mm of rain across 8.3 days. Temperatures run 21.5C down to 16.3C, and visitors split between finding it unexpectedly cold and finding the end of the month fine for walking. Tet falls in this month and makes trains and flights difficult around it. The figure to check is AQI 104. The record: humidity 78 percent and a 12 kph wind.

Regulars are consistent that nothing is certain weather-wise this month - some years start cool and warm up gradually, others start warm before a cold surge from the north drops temperatures 4-5 degrees, then it warms again toward month's end. Our row backs that mild, genuinely humid read, 24.7C over 19.5C nights, with 59mm of rain across 9.9 days and humidity climbing to 80 percent, alongside a notably low sunshine average, just 4.3 hours a day, reflecting the persistent drizzly, overcast skies regulars describe. Regulars are consistent that despite the unpredictability, this counts among the better months to visit overall, temperatures genuinely mild compared with the brutal summer heat still months away. Layers and a light rain jacket remain the standard packing advice regardless of which version of the month arrives. The record: a 13.5 kph wind and AQI 120.

Hanoi forum regulars confirm May runs genuinely hot: “low 30's to high 30's Celsius,” occasionally touching “39°C,” though the mid-30s are more common than the extreme end. It's very hot and humid, but regulars are clear May is not the wettest time of year — rain can happen any day, just not as a defining daily event yet, with no tropical storm risk this early in the season. The month splits in practice: early May it will be fine but it will be hot at the end of May, so timing matters even within the same 31 days. Standard packing: a poncho, sunscreen, light t-shirts and shorts, the transition between spring and full summer. Our record: 31.5°C days, feels-like 38°C, 15.6 rain days and an AQI of 113 — hot and humid with real rain risk, matching the “hot, gets hotter as the month goes on” read.

Travelers report daytime temperatures typically in the low-to-high 30s C, with one visitor logging a 44C reading during their June trip. The forum's repeated point is that humidity, not the raw heat number, is what actually wears people down, on top of the city's constant noise and often poor air quality. June also opens the rainy season, though the heaviest downpours usually don't arrive until later in the month - most rain comes as short, very heavy thunderstorms that can hit at any hour. The commonly shared coping strategy: start early, retreat indoors with air conditioning or a pool from around noon to 3pm, and hydrate constantly.

November is the best weather Hanoi gets — dry, 22-26°C, no humidity to speak of. December and January bring a damp grey drizzle that the numbers score as 'mild' but feels genuinely cold in an unheated old quarter house.

Hanoi's forum is clear that December is genuine winter by Vietnam standards — cool, dry days that can flip between t-shirt weather and a need for a proper fleece within 24 hours. Regulars note indoor heating is often minimal, so evenings indoors can feel colder than the daytime forecast suggests.