Hanoi sää — huhtikuu

April is the month the Ha Long forum names first: summer coming on, temperatures around 28C, mostly sunny, and ahead of the rainy season. It is also low season for visitor numbers apart from two dates - 30 April and 1 May, which are public holidays and fill everything. The caveat is visibility rather than rain. Fog can still shut the bay down, with boats held in harbour and cruises cancelled, and a milder haze is common enough that regulars argue it improves the view rather than spoils it. Our row's AQI of 95 is that haze with a number on it. The record: 27.2C days that feel like 31C, 22.2C nights, 11.5 precipitation days carrying 66.5mm, humidity 83 percent and a 25.7C sea.

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.

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.

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.